alternatehistory.com

Couping on the Thames
1989-2010: Kate Hoey (Labour)
def. 1989 By-election: Michael Keegan (Conservative), Mike Tuffrey (Social and Liberal Democrats), Henry Bewley (Green), 10 others (lost deposits)
def. 1992 (Conservative Government): Bernard Gentry (Conservative), Mike Tuffrey (Liberal Democrats), 2 others (lost deposits)
def. 1997 (Labour Government): Keith Kerr (Liberal Democrats), Richard Bacon (Conservative), 3 others (lost deposits)
def. 2001 (Labour Government): Anthony Bottrall (Liberal Democrats), Gareth Compton (Conservative), 3 others (lost deposits)
def. 2005 (Labour Government): Charles Anglin (Liberal Democrats), Edward Heckels (Conservative), 4 others (lost deposits)
2010-2015: Caroline Pidgeon (Liberal Democrats)
def. 2010 (Conservative Liberal Democrats Government): Steve Reed (Labour), Glyn Chambers (Conservative), 6 others (lost deposits)

So the premise is that the Council finally succeeds in getting Hoey deselected before the 2010 General Election and slots former Council Leader Steve Reed in. Hoey decides against standing as an Independent, and instead backs the LibDems as a way of spiting Reed. Labour suffers as the electorate disapproves of the stabbing in the back, but is unwilling to vote Conservative. Pidgeon subsequently wins the seat on a nats hair majority.