The fifteen or so years immediately after WWII are one of my special historical interests since it is the period when I grew up.
Some of the best books available are the following:
Peter Hennessy's book Never Again which is about Attlee's term (1945-51) exactly (he has just published his sequel Having it so good)
And ask your library to get you a copy of Age of Austerity, which is a book of essays edited by Michael Sissons and Philip French, which again covers the 1945-51 period.
But to understand the background to Attlee's term of office you also must read Paul Addison's books The Road to 1945 and Now the War is Over.
There are several biographies of Margaret Thatcher; other ABers will be able to recommend books covering that period.
I hope this is helpful (well, that's half your question answered, anyway).