UK's Top 100 Membership Bodies 2024

Posted by: Adam Weston

19 January 2024

Understanding the role of membership bodies and why digital matters

Membership bodies provide essential support, representation and professional resources to millions across the UK. From industry regulators to member-led associations, these organisations connect individuals and businesses through knowledge sharing, networking and professional development.

But while their purpose is constant, member expectations are not. Members want more than newsletters and renewals. They expect modern features like natural-language search, personalised content and services that help them grow.

In this article, we will look at the role of membership bodies and provide a list of the top 100 membership bodies in the UK based on membership.

By offering a platform for collaboration, knowledge sharing, and resource access, these bodies empower their members to enhance their professional development and achieve their objectives.

Understanding Membership Bodies

A membership body is an organisation that brings together individuals or businesses with shared interests, professions or goals. By offering a platform for collaboration and knowledge sharing, these bodies empower their members to improve their professional development and achieve their objectives. Whether they take the form of trade associations, industry organisations or professional bodies, membership organisations play a vital role in uniting like-minded individuals and fostering collective progress.

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The powerhouses of UK membership

Within the United Kingdom, membership bodies wield significant influence over their respective industries. As the collective voice of their members, these organisations advocate for their interests and provide unwavering support. The NUS, English Heritage, and the Caravan and Motorhome Club are among the giants in the UK's membership landscape.

Trade associations, featured in the UK Trade Association Directory, occupy a critical position within specific sectors. Trade associations foster collaboration, knowledge exchange and policy advocacy by effectively representing the interests of businesses and professionals.

Meanwhile, professional bodies in the UK focus on specific professions or disciplines. They establish industry standards, offer certifications and provide ongoing professional development opportunities. These bodies play a important role in upholding high standards of competence and ethics across various fields.

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Top 100 Membership Bodies in the UK

2024 Rank	Membership Organisation	2024 Members
1	National Union of Students (NUS)	7,000,000
2	Trades Union Congress (TUC)	5,500,000
3	National Trust	5,370,000
4	English Heritage	1,700,000
5	Unite	1,400,000
6	Unison	1,300,000
7	Royal Society for the Protection of Birds (RSPB)	1,200,000
8	Caravan and Motorhome Club	1,100,000
9	Wildlife Trusts	900,000
10	England Golf	737,000
11	Camping and Caravanning Club	700,000
12	Royal Horticultural Society (RHS)	600,000
13	GMB	570,000
14	The Scout Association	547,000
15	Royal College of Nursing (RCN)	500,000
16	Woodland Trust	500,000
17	National Education Union	445,000
18	University of the Third Age	430,000
19	Labour Party	395,000
20	Girlguiding UK	370,000
21	Oddfellows	369,000
22	Union of Shop Distributive and Allied Workers (USDAW)	360,000
23	British Gymnastics	400,000
24	National Trust for Scotland	300,000
25	NASUWT	300,000
26	Association of Chartered Certified Accountants (ACCA)	241,000
27	Law Society of England and Wales (TLS)	200,000
28	Historic Environment Scotland	200,000
29	Wildfowl and Wetlands Trust	200,000
30	Institute of Chartered Accountants of England and Wales (ICAEW)	198,500
31	British Medical Association (BMA)	190,366
32	Women’s Institute (WI)	190,000
33	Communication Workers Union (CWU)	185,000
34	Public and Commercial Services Union (PCS)	183,000
35	Royal British Legion (RBL)	180,000
36	Chartered Management Institute (CMI)	180,000
37	Wine Society	180,000
38	Campaign for Real Ale (CAMRA)s	136,645
39	United Grand Lodge of England	175,000
40	Conservative Party	172,000
41	Boundless (CSMA)	165,000
42	Chartered Institute of Personnel and Development (CIPD)	160,000
43	Prospect (Union)	157,000
44	Institution of Engineering and Technology (The IET)	154,000
45	British Association for Shooting and Conservation (BASC)	150,000
46	British Cycling	145,000
47	Police Federation of England and Wales	145,000
48	Chester Zoo	165,000
49	England Athletics	142,000
50	Tate Museum	142,000
51	Civil Service Sports Council (CSSC)	140,000
52	England and Great Britain Hockey	140,000
53	Art Fund	135,000
54	Royal Institution of Chartered Surveyors (RICS)	134,000
55	Youth Hostels Association (England and Wales)	130,000
56	Association of Accounting Technicians (AAT)	124,000
57	Chartered Insurance Institute (CII)	122,000
58	University and College Union (UCU)	120,000
59	British Horse Society (BHS)	120,000
60	Institution of Mechanical Engineers (IMechE)	115,000
61	Kew Gardens and Wakehurst	104,875
62	Scottish National Party	104,000
63	All England Netball	100,000
64	Royal Yachting Association (RYA)	100,000
65	Ramblers	100,000
66	Countryside Alliance	100,000
67	National Residential Landlords Association (NRLA)	100,000
68	World Wildlife Fund (WWF)	100,000
69	Institution of Civil Engineers (ICE)	95,000
70	Institute of the Motor Industry (IMI)	94,000
71	Arts Society (NADFAS)	90,000
72	British Canoeing	87,000
73	British Mountaineering Council	80,163
74	National Governance Association	80,000
75	Liberal Democrats	74,000
76	MotorSport Uk	70,000
77	British Computer Society (BCS)	70,000
78	Spotlight	70,000
79	Royal Air Forces Association	67,000
80	Chartered Society of Physiotherapy (CSP)	65,000
81	Coeliac UK	65,000
82	Chartered Institute of Procurement and Supply (CIPS)	64,000
83	Historic Houses	70,000
84	Educational Institute of Scotland	56,342
85	Green Party	54,000
86	Royal College of General Practitioners (RCGP)	54,000
87	English Bridge Union	54,000
88	British Psychological Society (BPS)	50,000
89	British Association for Counselling and Psychotherapy (BACP)	50,000
90	Royal Society of Chemistry (RSC)	50,000
91	Royal College of Midwives	50,000
92	Crohn’s & Colitis UK	50,000
93	Chartered Institute of Building (CIOB)	50,000
94	NEDonBoard	47,300
95	Equity	47,000
96	CADW	44,100
97	Institution of Occupational Safety and Health (IOSH)	44,000
98	Royal Institute of British Architects (RIBA)	28,000
99	Who are you? Get in touch if you think you rank.	-
100	Who are you? Get in touch if you think you rank.	-

Please note that this list is not exhaustive, as the UK boasts a vast array of membership bodies that cater to diverse industries and professions.

The role of Membership Bodies is empowering it's members

Membership bodies support their members by offering various benefits and services for professional growth, like facilitating networking opportunities and granting access to valuable resources. Some common responsibilities of membership bodies include:

Championing the interests of members on a national or industry level
Providing industry-specific research, insights, and market intelligence
Organising events, conferences, and seminars to foster networking and knowledge-sharing
Offering professional development programs, certifications, and training initiatives
Facilitating collaboration and partnerships within the industry
Granting access to resources, best practices, and industry-specific publications

Membership bodies act as a united force, pooling professionals' and businesses' expertise and collective efforts to drive industry growth, innovation, and success.

The UK’s Top 100 List of Membership Bodies 2024 is the result of extensive research and analysis.

Unveiling the source

The UK’s Top 100 List of Membership Bodies is derived from various sources, including annual reports, online directories, and membership organisation's websites. This list aims to showcase the membership bodies across various sectors in the UK based on member numbers.

If your organisation ranks in the top 100 get in touch

You'll find a link to the source in the table. If your membership organisation has more or fewer members than stated on this page, contact and provide the relevant link with the updated data. We'll happily change the information to provide the most accurate information available.

That said, many organisations are rounding up their quoted numbers or haven't updated them recently, and it would be great to have more accurate figures for 2024.

Our objective in compiling this list is to provide a valuable resource for individuals and businesses seeking to connect with relevant membership bodies and leverage their benefits.

For more information about membership bodies in the UK, please visit the respective websites of the organisations mentioned in this post.