| Llandaff and Barry |
Full name (in Craig 3) Glamorganshire, Llandaff and Barry |
| Llanelli |
Full name (in Craig 4) Carmarthenshire, Llanelli. Spelled Llanelly between 1918 and 1950 - not strictly a new seat in that year. |
| Llanelly |
Full name (in Craig 3) Carmarthenshire, Llanelly. Spelling changed to Llanelli (q.v.) in 1950 - not strictly a redistribution. |
| Londonderry [borough] |
|
| Londonderry [county] |
Constituency of same name also existed 1922-1983. |
| Londonderry [county] |
Constituency of same name also existed 1832-1885. |
| Londonderry East |
|
| Londonderry North |
|
| Londonderry South |
|
| London University |
Non-geographic constituency. |
| Longford |
Constituency of same name also existed 1832-1885. |
| Longford |
Constituency of same name also existed 1918-1922. |
| Longford North |
|
| Longford South |
|
| Lonsdale |
Full name (in Craig 3) Lancashire, Lonsdale |
| Loughborough |
Full name (in Craig 2,3,4) Leicestershire, Loughborough |
| Louth and Horncastle |
|
| Louth [borough, Lincolnshire] |
Full name (in Craig 2,3,4) Lincolnshire and Rutlandshire (parts of Lindsey), Louth |
| Louth [county, Ireland] |
Constituency of same name also existed 1832-1885. |
| Louth [county, Ireland] |
Constituency of same name also existed 1918-1922. |