This blogger mentions Tony Blair and GKC in the same post. Both are famous Catholic converts. Or at least Blair appears to be heading that way.
"Anyways, Mr. Blair would join a long list of British luminaries to convert to Catholicism which includes G.K. Chesterton, Sir Alec Guinness, Graham Leonard (former Anglican Bishop of London), John Henry Newman, and J.R.R. Tolkein just to name a few."