In this period, members of the European Parliament were not directly elected, but were chosen by and from among the members of the House of Commons and House of Lords as delegates. The total size of the United Kingdom delegation was 36 but the Labour Party refused to name its delegates because of the party's then policy of opposing British membership of the European Communities. After the 1975 referendum, Labour decided to take its seats.
| Name | Party | Dates | |
A | |||
| Lord Ardwick | Labour | 3 July 1975 - 1979 | |
B | |||
| Guy Barnett | Labour | 1 July 1975 - 24 May 1976 | |
| Sir Tufton Beamish | Conservative | 1 January 1973 - 24 July 1974 | |
| Earl of Bessborough | Conservative | 1 January 1973 - 1979 | |
| Lord Bethell | Conservative | 10 March 1975 - 1979 | |
| Betty Boothroyd | Labour | 1 July 1975 - 1 March 1977 | |
| Lord Brecon | Conservative | 1 January 1973 - 24 October 1973 | |
| John Brewis | Conservative | 1 January 1973 - 28 February 1975 | |
| Lord Brimelow | Labour | 28 February 1977 - 30 June 1978 | |
| Ronald Brown | Labour | 1 March 1977 - 1979 | |
| Lord Bruce of Donington | Labour | 3 July 1975 - 1979 | |
C | |||
| Lord Castle | Labour | 3 July 1975 - 1979 | |
| John Corrie | Conservative | 28 February 1975 - 18 December 1975; 1 March 1977 - 1979 | |
| George Cunningham | Labour | 13 March 1978 - 1979 | |
D | |||
| Tam Dalyell | Labour | 1 July 1975 - 1979 | |
| Sir Geoffrey de Freitas | Labour | 1 July 1975 - 1979 | |
| Sir Douglas Dodds-Parker | Conservative | 1 January 1973 - 28 February 1975 | |
| Gwyneth Dunwoody | Labour | 1 July 1975 - 1979 | |
| Hugh Dykes | Conservative | 24 July 1974 - 1 March 1977 | |
E | |||
| Robert Edwards | Labour | 1 March 1977 - 1979 | |
| Baroness Elles | Conservative | 1 January 1973 - 3 July 1975 | |
| Tom Ellis | Labour | 1 July 1975 - 1979 | |
| John Evans | Labour | 1 July 1975 - 13 March 1978 | |
| Winnie Ewing | SNP | 7 July 1975 - 1979 | |
F | |||
| Peggy Fenner | Conservative | 24 July 1974 - 28 February 1975 | |
| Baroness Fisher of Rednal | Labour | 3 July 1975 - 1979 | |
| Alan Fitch | Labour | 13 March 1978 - 1979 | |
| Alex Fletcher | Conservative | 18 December 1975 - 1 March 1977 | |
| Charles Fletcher-Cooke | Conservative | 1 March 1977 - 1979 | |
G | |||
| Lord Gladwyn | Liberal | 1 January 1973 - 3 July 1975; 8 July 1975 - 1 October 1976 | |
| Lord Gordon-Walker | Labour | 3 July 1975 - 20 October 1976 | |
H | |||
| Willie Hamilton | Labour | 1 July 1975 - 1979 | |
| James Hill | Conservative | 1 January 1973 - 28 February 1975 | |
| John Hill | Conservative | 1 January 1973 - 24 July 1974 | |
| Ralph Howell | Conservative | 24 July 1974 - 1979 | |
| Mark Hughes | Labour | 1 July 1975 - 1979 | |
J | |||
| Russell Johnston | Liberal | 1 January 1973 - 7 July 1975; 1 October 1976 - 1979 | |
K | |||
| Elaine Kellett-Bowman | Conservative | 28 February 1975 - 1979 | |
| Lord Kennet | Labour | 28 February 1978 - 1979 | |
| Peter Kirk | Conservative | 1 January 1973 - 17 April 1977 | |
L | |||
| Marquess of Lothian | Conservative | 24 October 1973 - 3 July 1975 | |
M | |||
| Earl of Mansfield and Mansfield | Conservative | 1 January 1973 - 10 March 1975 | |
| Bob Mitchell | Labour | 1 July 1975 - 1979 | |
| William Molloy | Labour | 24 May 1976 - 1 March 1977 | |
| Lord Murray of Gravesend | Labour | 20 October 1976 - 28 February 1978; 30 June 1978 - 1979 | |
N | |||
| Tom Normanton | Conservative | 1 January 1973 - 1979 | |
O | |||
| Lord O'Hagan | Cross-bencher | 1 January 1973 - 3 July 1975 | |
| John Osborn | Conservative | 28 February 1975 - 1979 | |
P | |||
| John Peel | Conservative | 1 January 1973 - 24 July 1974 | |
| Rafton Pounder | Ulster Unionist | 1 January 1973 - 24 July 1974 | |
| John Prescott | Labour | 1 July 1975 - 1979 | |
| Christopher Price | Labour | 1 March 1977 - 13 March 1978 | |
R | |||
| Lord Reay | Conservative | 1 January 1973 - 1979 | |
| Sir Brandon Rhys Williams, Bt. | Conservative | 1 January 1973 - 1979 | |
| Geoffrey Rippon | Conservative | 6 May 1977 - 1979 | |
S | |||
| Lord St Oswald | Conservative | 1 January 1973 - 1979 | |
| James Scott-Hopkins | Conservative | 1 January 1973 - 1979 | |
| Michael Shaw | Conservative | 24 July 1974 - 1979 | |
| James Spicer | Conservative | 28 February 1975 - 1979 | |
| Michael Stewart | Labour | 1 July 1975 - 19 November 1976 | |
T | |||
| Dick Taverne | Democratic Labour | 4 April 1973 - 10 October 1974 | |
| Frank Tomney | Labour | 19 November 1976 - 1 March 1977 | |
W | |||
| Sir Derek Walker-Smith | Conservative | 1 January 1973 - 1979 | |
| Lord Walston | Labour | 3 July 1975 - 28 February 1977 | |