alternatehistory.com

Blair manages to get a referendum on the Euro - for July 2003. He subsequently loses, handing over power to Brown, who barely hangs on in 2006 and loses in 2011 to Cameron.

1997-2003: Tony Blair (Labour)
def. 1997 (Labour majority): John Major (Conservative), Paddy Ashdown (Liberal Democrat)
def. 2001 (Labour majority): William Hague (Conservative), Charles Kennedy (Liberal Democrat)
2003-2011: Gordon Brown (Labour)
def. 2006 (Labour majority): David Cameron (Conservative), Charles Kennedy (Liberal Democrat)
2011-2017: David Cameron (Conservative)
def. 2011 (Conservative majority): Gordon Brown (Labour), Chris Huhne (Liberal Democrat)
def. 2016 (Conservative-Liberal Democrat coalition): Ed Balls (Labour), Nick Clegg (Liberal Democrat)