#YourDataLeak: Your Party’s Membership Numbers Belong to Members

A potential glitch on Your Party's website made 651 constituency member counts available to YP logged-in members for six hours in November. I am here releasing the dataset in full.

[UPDATE: Jump to Map of Density per Constituency]

Your Party is now a national organisation with tens of thousands of members spread across every constituency in Britain. Somewhere inside its systems, there is a living map of that membership: where members live, which branches are larger, which areas are strong or dense. That map is not neutral. In the wrong hands, it is another instrument for shaping the fast approaching CEC elections and consolidating control of the collective leadership.

For most of the founding period, only a tiny circle around the leadership had access to that map. Members were made to self-organise 190 proto-branches reported to have sprung up around the country, to vote on constitutional amendments, and decide factional strategies largely in the dark (and with no resources). Then, on the 20th of November, the Your Party member portal deliberately or accidentally exposed branch membership numbers and member profile pages to any logged-in member. Less than six hours later, the information was gone. It appears though that someone, using automated tools, or what is often called “scraping”, collected the membership counts for every constituency in Great Britain and Northern Ireland while that window was open.

To be clear about what follows:

• I do not have, and I am not publishing, any personal profile data (names, bios, social media accounts, etc.).

• The only data I am publishing is aggregated, anonymous membership counts per constituency as they appeared on that day.

• The full anonymous dataset was not produced by me; it appears to have been collected from Your Party’s own public member portal while the numbers were briefly visible using methods of automation. I cannot verify the method, only the shape of the resulting data, and the total figures - that incidentally match the membership total that the leadership reported at the time.

• It was sent to me anonymously

What members could see that day, if they logged in quickly enough, was:

• which local groups (branches) existed,

• which branch they belonged to,

• member profiles within those groups (for those who had chosen to make their profile visible),

• and, crucially, the total number of members per constituency or branch.

To my knowledge, only the membership numbers were systematically collected during that short window. Whether anyone also captured the personal profiles is unknown and would raise data‑protection questions for both whoever did so and for the party’s leadership. That is not the avenue I am taking. The question here is simpler: should basic, non‑personal membership statistics be centralised at the top, or shared democratically with the membership?

This is important because whoever holds this kind of information holds a major advantage in any internal election.

In the Cambridge Analytica scandal, millions of Facebook profiles were harvested and matched with psychographic models to deliver highly targeted political ads. Researchers and journalists have argued that this kind of micro‑targeting played a role in shaping opinion in the Brexit referendum and the 2016 US elections, not by brainwashing people, but by allowing campaigns to focus resources on precisely identified groups in ways their opponents could not match. Data plus adverts equals leverage.

Inside a party, you don’t need Cambridge Analytica‑level psychographics to make a difference. If one faction or leadership circle has:

• a list of where every member lives,

• which branches are large or small,

• and which areas are electorally important, they can concentrate their efforts - social media ads, targeted emails, visits, phone‑banking - on the most strategically useful seats and members. Those without that map are left organising blind.

During Your Party’s founding phase, this is exactly the asymmetry we saw. As I argued in my Candidate Transparency Statement piece, the leadership ”held all membership data, set all rules and criteria for document processing, determined which submissions became ‘evolutions’ versus ‘amendments,’ and made these decisions unilaterally with no member oversight.” Meanwhile, ordinary members squeezed every drop of information out of whatever fragments they could find, desperately trying to map an organisation they were meant to be sovereign over. The disparity of information access between the two main factions involved in the dispute of Your Party through its founding months amounts to a classic case of information asymmetry.

The member profile information, with names, bios, interests, social media profiles, remains in the hands of the party. That is as it should be, provided it is properly protected and never abused. The point here is not to accuse data officers of wrongdoing, but to illustrate in concrete terms who holds the levers and who does not. When only the leadership knows where the members are and how many there are, internal democracy starts with a tilted playing field.

The only part of this hidden map that has been made available outside that inner circle is the anonymous membership counts exposed on 20th November 2025. The dataset below lists, for each Westminster constituency, the number of members assigned to that branch on that day. The total is around 53,300 members. As the data came from public profile pages inside the portal, it may slightly under‑count members who chose not to make their profile visible, but it is the most complete anonymous snapshot members have seen so far.

Publishing these anonymous counts is, in my view, both legitimate, because no personal data is exposed; only numbers per constituency are shared, and necessary, because without this information, members cannot understand the basic structure of their own party or organise effectively across regions in the run-up to the CEC elections.

Democratising this dataset is a small step towards correcting the information asymmetry between leadership and membership. It returns non‑sensitive information to where it belongs: in the hands of the people whose subscriptions and labour built the party in the first place, rather than being treated as proprietary intelligence available only to those already in positions of power.

The full dataset is therefore published below as well as in a public spreadsheet that includes the hard data (the actual numbers per branch) locked in but allows for the collective intelligence to crunch numbers, add formulas, new sheets and cross it over with other public data within the public google sheet to elicit new information of value to the membership, and share with an ethos of transparency and democracy.

[update]

Click on image to visit interactive map

Candidate Transparency Statements, as argued in my previous article, are about who is asking to lead - their class position, economic interests, and political employment. Data transparency is about what tools they and headquarters have at their disposal when they do so. Just as Candidate Transparency Statements would expose the structural position of those asking to lead, democratised access to basic membership statistics exposes the structural terrain on which internal contests are fought.

What follows is the dataset itself:

Constituency	Members
Aberafan Maesteg	51
Aberdeen North	50
Aberdeen South	54
Aberdeenshire North and Moray East	27
Airdrie and Shotts	38
Aldershot	57
Aldridge-Brownhills	46
Alloa and Grangemouth	35
Altrincham and Sale West	55
Alyn and Deeside	54
Amber Valley	55
Angus and Perthshire Glens	52
Arbroath and Broughty Ferry	39
Argyll, Bute and South Lochaber	69
Arundel and South Downs	53
Ashfield	50
Ashford	43
Ashton-under-Lyne	74
Aylesbury	61
Ayr, Carrick and Cumnock	41
Banbury	66
Bangor Aberconwy	116
Barking	74
Barnsley North	52
Barnsley South	56
Barrow and Furness	97
Basildon and Billericay	37
Basingstoke	57
Bassetlaw	51
Bath	110
Bathgate and Linlithgow	48
Battersea	85
Beaconsfield	36
Beckenham and Penge	110
Bedford	68
Belfast East	19
Belfast North	30
Belfast South and Mid Down	58
Belfast West	18
Bermondsey and Old Southwark	154
Berwickshire, Roxburgh and Selkirk	62
Bethnal Green and Stepney	222
Beverley and Holderness	69
Bexhill and Battle	96
Bexleyheath and Crayford	44
Bicester and Woodstock	79
Birkenhead	182
Birmingham Edgbaston	99
Birmingham Erdington	71
Birmingham Hall Green and Moseley	143
Birmingham Hodge Hill and Solihull North	63
Birmingham Ladywood	114
Birmingham Northfield	80
Birmingham Perry Barr	105
Birmingham Selly Oak	116
Birmingham Yardley	70
Bishop Auckland	72
Blackburn	81
Blackley and Middleton South	100
Blackpool North and Fleetwood	73
Blackpool South	67
Blaenau Gwent and Rhymney	41
Blaydon and Consett	104
Blyth and Ashington	77
Bognor Regis and Littlehampton	54
Bolsover	65
Bolton North East	79
Bolton South and Walkden	64
Bolton West	85
Bootle	202
Boston and Skegness	37
Bournemouth East	88
Bournemouth West	74
Bracknell	41
Bradford East	69
Bradford South	52
Bradford West	94
Braintree	58
Brecon, Radnor and Cwm Tawe	138
Brent East	138
Brent West	69
Brentford and Isleworth	116
Brentwood and Ongar	42
Bridgend	59
Bridgwater	50
Bridlington and The Wolds	45
Brigg and Immingham	47
Brighton Kemptown and Peacehaven	261
Brighton Pavilion	380
Bristol Central	214
Bristol East	241
Bristol North East	197
Bristol North West	102
Bristol South	151
Broadland and Fakenham	61
Bromley and Biggin Hill	62
Bromsgrove	44
Broxbourne	44
Broxtowe	89
Buckingham and Bletchley	66
Burnley	79
Burton and Uttoxeter	69
Bury North	68
Bury South	102
Bury St Edmunds and Stowmarket	77
Caerfyrddin	113
Caerphilly	76
Caithness, Sutherland and Easter Ross	62
Calder Valley	213
Camborne and Redruth	132
Cambridge	178
Cannock Chase	43
Canterbury	151
Cardiff East	139
Cardiff North	93
Cardiff South and Penarth	103
Cardiff West	94
Carlisle	89
Carshalton and Wallington	68
Castle Point	29
Central Ayrshire	37
Central Devon	123
Central Suffolk and North Ipswich	53
Ceredigion Preseli	152
Chatham and Aylesford	47
Cheadle	85
Chelmsford	65
Chelsea and Fulham	89
Cheltenham	57
Chesham and Amersham	44
Chester North and Neston	121
Chester South and Eddisbury	81
Chesterfield	81
Chichester	67
Chingford and Woodford Green	122
Chippenham	71
Chipping Barnet	109
Chorley	71
Christchurch	47
Cities of London and Westminster	132
City of Durham	92
Clacton	53
Clapham and Brixton Hill	146
Clwyd East	97
Clwyd North	77
Coatbridge and Bellshill	36
Colchester	117
Colne Valley	117
Congleton	57
Corby and East Northamptonshire	71
Coventry East	74
Coventry North West	104
Coventry South	144
Cowdenbeath and Kirkcaldy	43
Cramlington and Killingworth	84
Crawley	61
Crewe and Nantwich	74
Croydon East	77
Croydon South	75
Croydon West	95
Cumbernauld and Kirkintilloch	36
Dagenham and Rainham	63
Darlington	55
Dartford	55
Daventry	45
Derby North	64
Derby South	37
Derbyshire Dales	88
Dewsbury and Batley	65
Didcot and Wantage	71
Doncaster Central	78
Doncaster East and the Isle of Axholme	47
Doncaster North	47
Dorking and Horley	45
Dover and Deal	110
Droitwich and Evesham	48
Dudley	39
Dulwich and West Norwood	200
Dumfries and Galloway	64
Dumfriesshire, Clydesdale and Tweeddale	56
Dundee Central	71
Dunfermline and Dollar	42
Dunstable and Leighton Buzzard	68
Dwyfor Meirionnydd	99
Ealing Central and Acton	160
Ealing North	79
Ealing Southall	87
Earley and Woodley	43
Easington	63
East Antrim	17
East Grinstead and Uckfield	63
East Ham	96
East Hampshire	48
East Kilbride and Strathaven	47
East Londonderry	10
East Renfrewshire	47
East Surrey	52
East Thanet	162
East Wiltshire	40
East Worthing and Shoreham	143
Eastbourne	99
Eastleigh	49
Edinburgh East and Musselburgh	160
Edinburgh North and Leith	178
Edinburgh South	110
Edinburgh South West	75
Edinburgh West	75
Edmonton and Winchmore Hill	103
Ellesmere Port and Bromborough	117
Eltham and Chislehurst	70
Ely and East Cambridgeshire	83
Enfield North	105
Epping Forest	48
Epsom and Ewell	45
Erewash	65
Erith and Thamesmead	115
Esher and Walton	47
Exeter	116
Exmouth and Exeter East	87
Falkirk	45
Fareham and Waterlooville	46
Farnham and Bordon	40
Faversham and Mid Kent	56
Feltham and Heston	59
Fermanagh and South Tyrone	11
Filton and Bradley Stoke	75
Finchley and Golders Green	122
Folkestone and Hythe	106
Forest of Dean	86
Foyle	23
Frome and East Somerset	124
Fylde	72
Gainsborough	49
Gateshead Central and Whickham	101
Gedling	102
Gillingham and Rainham	51
Glasgow East	112
Glasgow North	149
Glasgow North East	69
Glasgow South	148
Glasgow South West	113
Glasgow West	104
Glastonbury and Somerton	94
Glenrothes and Mid Fife	37
Gloucester	75
Godalming and Ash	44
Goole and Pocklington	54
Gordon and Buchan	39
Gorton and Denton	144
Gosport	47
Gower	104
Grantham and Bourne	42
Gravesham	55
Great Grimsby and Cleethorpes	67
Great Yarmouth	57
Greenwich and Woolwich	138
Guildford	58
Hackney North and Stoke Newington	299
Hackney South and Shoreditch	266
Halesowen	53
Halifax	80
Hamble Valley	49
Hamilton and Clyde Valley	42
Hammersmith and Chiswick	115
Hampstead and Highgate	196
Harborough, Oadby and Wigston	72
Harlow	64
Harpenden and Berkhamsted	61
Harrogate and Knaresborough	70
Harrow East	50
Harrow West	68
Hartlepool	52
Harwich and North Essex	87
Hastings and Rye	263
Havant	35
Hayes and Harlington	49
Hazel Grove	90
Hemel Hempstead	50
Hendon	79
Henley and Thame	53
Hereford and South Herefordshire	76
Herne Bay and Sandwich	91
Hertford and Stortford	53
Hertsmere	36
Hexham	84
Heywood and Middleton North	67
High Peak	95
Hinckley and Bosworth	58
Hitchin	64
Holborn and St Pancras	248
Honiton and Sidmouth	64
Hornchurch and Upminster	49
Hornsey and Friern Barnet	256
Horsham	49
Houghton and Sunderland South	48
Hove and Portslade	258
Huddersfield	101
Huntingdon	48
Hyndburn	50
Ilford North	106
Ilford South	82
Inverclyde and Renfrewshire West	35
Inverness, Skye and West Ross-shire	73
Ipswich	88
Isle of Wight East	50
Isle of Wight West	55
Islington North	405
Islington South and Finsbury	218
Jarrow and Gateshead East	76
Keighley and Ilkley	82
Kenilworth and Southam	72
Kensington and Bayswater	118
Kettering	67
Kilmarnock and Loudoun	25
Kingston and Surbiton	85
Kingston upon Hull East	59
Kingston upon Hull North and Cottingham	158
Kingston upon Hull West and Haltemprice	76
Kingswinford and South Staffordshire	24
Knowsley	139
Lagan Valley	13
Lancaster and Wyre	132
Leeds Central and Headingley	151
Leeds East	79
Leeds North East	143
Leeds North West	87
Leeds South	80
Leeds South West and Morley	66
Leeds West and Pudsey	101
Leicester East	44
Leicester South	113
Leicester West	88
Leigh and Atherton	66
Lewes	112
Lewisham East	132
Lewisham North	237
Lewisham West and East Dulwich	220
Leyton and Wanstead	211
Lichfield	39
Lincoln	98
Liverpool Garston	223
Liverpool Riverside	303
Liverpool Walton	159
Liverpool Wavertree	311
Liverpool West Derby	180
Livingston	42
Llanelli	77
Lothian East	51
Loughborough	68
Louth and Horncastle	78
Lowestoft	70
Luton North	75
Luton South and South Bedfordshire	75
Macclesfield	80
Maidenhead	56
Maidstone and Malling	39
Makerfield	74
Maldon	39
Manchester Central	169
Manchester Rusholme	237
Manchester Withington	282
Mansfield	39
Melksham and Devizes	70
Melton and Syston	38
Meriden and Solihull East	63
Merthyr Tydfil and Aberdare	84
Mid and South Pembrokeshire	91
Mid Bedfordshire	49
Mid Buckinghamshire	32
Mid Cheshire	70
Mid Derbyshire	52
Mid Dorset and North Poole	38
Mid Dunbartonshire	43
Mid Leicestershire	66
Mid Norfolk	54
Mid Sussex	65
Mid Ulster	16
Middlesbrough and Thornaby East	67
Middlesbrough South and East Cleveland	64
Midlothian	48
Milton Keynes Central	67
Milton Keynes North	98
Mitcham and Morden	102
Monmouthshire	80
Montgomeryshire and Glyndwr	105
Moray West, Nairn and Strathspey	43
Morecambe and Lunesdale	90
Motherwell, Wishaw and Carluke	37
Na h-Eileanan an Iar	24
Neath and Swansea East	58
New Forest East	40
New Forest West	35
Newark	66
Newbury	40
Newcastle upon Tyne Central and West	97
Newcastle upon Tyne East and Wallsend	143
Newcastle upon Tyne North	131
Newcastle-under-Lyme	63
Newport East	88
Newport West and Islwyn	46
Newry and Armagh	14
Newton Abbot	66
Newton Aycliffe and Spennymoor	69
Normanton and Hemsworth	81
North Antrim	14
North Ayrshire and Arran	55
North Bedfordshire	53
North Cornwall	84
North Cotswolds	58
North Devon	76
North Dorset	47
North Down	20
North Durham	66
North East Cambridgeshire	39
North East Derbyshire	64
North East Fife	55
North East Hampshire	44
North East Hertfordshire	64
North East Somerset and Hanham	78
North Herefordshire	47
North Norfolk	67
North Northumberland	87
North Shropshire	60
North Somerset	84
North Warwickshire and Bedworth	42
North West Cambridgeshire	64
North West Essex	52
North West Hampshire	44
North West Leicestershire	49
North West Norfolk	58
Northampton North	79
Northampton South	58
Norwich North	93
Norwich South	175
Nottingham East	175
Nottingham North and Kimberley	55
Nottingham South	76
Nuneaton	47
Old Bexley and Sidcup	48
Oldham East and Saddleworth	53
Oldham West, Chadderton and Royton	65
Orkney and Shetland	28
Orpington	40
Ossett and Denby Dale	70
Oxford East	148
Oxford West and Abingdon	109
Paisley and Renfrewshire North	43
Paisley and Renfrewshire South	50
Peckham	192
Pendle and Clitheroe	92
Penistone and Stocksbridge	63
Penrith and Solway	92
Perth and Kinross-shire	52
Peterborough	71
Plymouth Moor View	58
Plymouth Sutton and Devonport	133
Pontefract, Castleford and Knottingley	60
Pontypridd	79
Poole	64
Poplar and Limehouse	163
Portsmouth North	69
Portsmouth South	120
Preston	86
Putney	91
Queen’s Park and Maida Vale	159
Rawmarsh and Conisbrough	63
Rayleigh and Wickford	35
Reading Central	95
Reading West and Mid Berkshire	46
Redcar	87
Redditch	38
Reigate	45
Rhondda and Ogmore	63
Ribble Valley	73
Richmond and Northallerton	51
Richmond Park	99
Rochdale	61
Rochester and Strood	58
Romford	49
Romsey and Southampton North	69
Rossendale and Darwen	74
Rother Valley	58
Rotherham	56
Rugby	70
Ruislip, Northwood and Pinner	73
Runcorn and Helsby	107
Runnymede and Weybridge	48
Rushcliffe	94
Rutherglen	52
Rutland and Stamford	50
Salford	146
Salisbury	61
Scarborough and Whitby	110
Scunthorpe	57
Sefton Central	149
Selby	50
Sevenoaks	40
Sheffield Brightside and Hillsborough	94
Sheffield Central	212
Sheffield Hallam	137
Sheffield Heeley	184
Sheffield South East	53
Sherwood Forest	68
Shipley	113
Shrewsbury	95
Sittingbourne and Sheppey	41
Skipton and Ripon	80
Sleaford and North Hykeham	53
Slough	64
Smethwick	55
Solihull West and Shirley	58
South Antrim	19
South Basildon and East Thurrock	24
South Cambridgeshire	88
South Cotswolds	51
South Derbyshire	42
South Devon	119
South Dorset	109
South Down	14
South East Cornwall	113
South Holland and The Deepings	35
South Leicestershire	54
South Norfolk	72
South Northamptonshire	59
South Ribble	78
South Shields	86
South Shropshire	79
South Suffolk	58
South West Devon	73
South West Hertfordshire	42
South West Norfolk	52
South West Wiltshire	74
Southampton Itchen	105
Southampton Test	106
Southend East and Rochford	69
Southend West and Leigh	70
Southgate and Wood Green	223
Southport	128
Spelthorne	44
Spen Valley	55
St Albans	59
St Austell and Newquay	97
St Helens North	105
St Helens South and Whiston	96
St Ives	133
St Neots and Mid Cambridgeshire	71
Stafford	56
Staffordshire Moorlands	50
Stalybridge and Hyde	82
Stevenage	74
Stirling and Strathallan	51
Stockport	147
Stockton North	68
Stockton West	54
Stoke-on-Trent Central	65
Stoke-on-Trent North	41
Stoke-on-Trent South	58
Stone, Great Wyrley and Penkridge	40
Stourbridge	49
Strangford	7
Stratford and Bow	207
Stratford-on-Avon	42
Streatham and Croydon North	145
Stretford and Urmston	161
Stroud	104
Suffolk Coastal	57
Sunderland Central	103
Surrey Heath	34
Sussex Weald	55
Sutton and Cheam	63
Sutton Coldfield	57
Swansea West	110
Swindon North	59
Swindon South	75
Tamworth	43
Tatton	62
Taunton and Wellington	74
Telford	77
Tewkesbury	46
The Wrekin	55
Thirsk and Malton	56
Thornbury and Yate	66
Thurrock	43
Tipton and Wednesbury	30
Tiverton and Minehead	94
Tonbridge	47
Tooting	104
Torbay	68
Torfaen	49
Torridge and Tavistock	100
Tottenham	263
Truro and Falmouth	142
Tunbridge Wells	88
Twickenham	79
Tynemouth	111
Upper Bann	5
Uxbridge and South Ruislip	78
Vale of Glamorgan	72
Vauxhall and Camberwell Green	139
Wakefield and Rothwell	91
Wallasey	251
Walsall and Bloxwich	78
Walthamstow	242
Warrington North	76
Warrington South	82
Warwick and Leamington	89
Washington and Gateshead South	64
Watford	71
Waveney Valley	59
Weald of Kent	43
Wellingborough and Rushden	63
Wells and Mendip Hills	85
Welwyn Hatfield	69
West Aberdeenshire and Kincardine	29
West Bromwich	36
West Dorset	105
West Dunbartonshire	47
West Ham and Beckton	99
West Lancashire	120
West Suffolk	55
West Tyrone	19
West Worcestershire	66
Westmorland and Lonsdale	82
Weston-super-Mare	76
Wetherby and Easingwold	53
Whitehaven and Workington	62
Widnes and Halewood	103
Wigan	79
Wimbledon	103
Winchester	44
Windsor	48
Wirral West	119
Witham	52
Witney	56
Woking	47
Wokingham	44
Wolverhampton North East	36
Wolverhampton South East	29
Wolverhampton West	81
Worcester	67
Worsley and Eccles	100
Worthing West	96
Wrexham	68
Wycombe	59
Wyre Forest	54
Wythenshawe and Sale East	125
Yeovil	50
Ynys Mon	1
York Central	164
York Outer	75