David Harvey, a member of the council since 1998, was one of two Conservative cabinet members to lose their seats as Witney South went to Labour’s Ruth Smith by 69 votes.
The cabinet member for housing and communities Merilyn Davies also lost by 131 votes to Liberal Democrat Lidia Arciszewska.
The Tories lost seven of the 11 seats they were contesting – five to the Liberal Democrats and one each to Labour and the Green Party – with no gains, losing control of the council for the first time in more than 20 years.
The shift means the Liberal Democrats, Labour and Green Party are set to form a majority, much like the Fair Deal Alliance put together at Oxfordshire County Council last year, to run the show. They now have 26 of the council's 49 seats between them.
Mr Harvey referred to “a number of different factors”.
“Certainly, I am sorry that I won’t be carrying forward the climate change agenda on the district council,” he said.
“It is a very important agenda and something we are doing very well with.
“After nearly a quarter of a century on the district council I think we have achieved a huge amount and I wish Godspeed to those who are still on the council, I wish them well with taking forward the agendas.”
Asked what those factors were, Mr Harvey replied: “The size of the turnout, I think there was also possibly a certain disaffection with the election system. People seem to be a little bit weary.”
There was much talk about what impact partygate and the state of national politics would have in the build up to polling, particularly for the Conservatives, but the prime minister did not come in for a bashing from Mr Harvey.
“I think he is in a very difficult position,” he said.
“I think his leadership on the question of Ukraine has been outstanding. As far as the other issues are concerned I don’t really have a view but national politics generally, I think they may have been reflected in the results.”