Post by Don PhillipsonThis is not a matter of law (in the British unwritten constitution) but
merely social consensus, which by the 20th century disapproved any
prime minister in the House of Lords. The last was Lord Salisbury
(last in office 1895-1902.) The new convention excluded Lord Curzon
from Tory leadership in the 1920s and Lord Halifax in 1940.
It was not a strict prohibition until after the 1940s.
When the Liberals won the election of 1905, their leader
was Henry Campbell-Bannerman, and therefore PM. Three of
the leading Liberals tried to force him to accept a
peerage and therefore go to the House of Lords.
When Bonar Law resigned as PM in 1923, Curzon expected
to replace him, and was shocked and disappointed when
Baldwin got the nod instead.
As for Halifax in 1940, his peerage was only a minor
issue. Most of the Conservatives preferred him over
the volatile Churchill. Even Labour would accept him;
Beaverbrook wrote that "Labour wanted Halifax." The
real obstacle was that Halifax himself thought
Churchill was more suitable (and more powerful as a
personality). He wrote later that it seemed to him if
he became PM, with Churchill effectively running the
war, he would be a figurehead.
However, the peerage question was definitely becoming
a barrier, and by the 1960s, it was necessary for Alec
Douglas-Home to disclaim his peerage to become PM.
--
The real Velvet Revolution - and the would-be hijacker.
http://originalvelvetrevolution.com