| Ulster Farmers' Union |
Pressure/campaign organisations |
|
| Ulster Unionist Council |
Party-affiliated organisations |
|
| Ulster Unionist Labour Association |
Pressure/campaign organisations |
|
| Union Defence League |
Pressure/campaign organisations |
|
| Unionist Association |
Party-affiliated organisations |
|
| Unionist Free Trader |
Pressure/campaign organisations |
|
| Unionist Labour |
Party-affiliated organisations |
|
| Unionist Workers' League |
Pressure/campaign organisations |
|
| Union of Democratic Control |
Pressure/campaign organisations |
|
| Unitarian |
Religious organisations |
|
| United Empire Trade League |
Pressure/campaign organisations |
|
| United Free Church |
Religious organisations |
|
| United Irish League |
Miscellaneous |
|
| United Kingdom Alliance |
Pressure/campaign organisations |
|
| United Kingdom Band of Hope Union |
Religious organisations |
|
| United Kingdom Commercial Travellers' Association |
Pressure/campaign organisations |
|
| United Law Society |
Professional/trade organisations |
|
| United Nations Association |
International organisations |
|
| United Synagogue |
Religious organisations |
|
| UPUK Alliance |
Party-affiliated organisations |
|
| Urban District Councils Association |
Miscellaneous |
|