Fatherland is set in Germany rather than the UK. It’s more than 30 years since I read it, so there might conceivably be a passing reference to Oxford. Knowing quite a lot about Hitler’s Germany, and many of the leading Nazis, I thought it was an excellent, absorbing book, very well researched.
More recently, I’ve read Robert Harris’s Munich dealing with the 1938 conference in that city. Again, very well researched, but not as gripping as Fatherland.
I’ve read many of Harris’s other books that have been mentioned in this thread. A couple of years ago I read Act of Oblivion, which is about the post-Restoration hunt for regicides who sentenced Charles I to death in 1649. It was OK, but I much preferred a factual book on the subject by Charles Spencer entitled Killers of the King.