Energy and Climate Change Minister Greg Barker is leaving government and will not seek re-election next year.
He said he was "very pleased" to have served in environment and climate change posts for 10 years in opposition and Government and had a "terrific time".
"For me it's time to seek new challenges. I remain 110% supportive of the Prime Minister and his ambition for Britain," Mr Barker added.
PMQs today was a pretty clear win for David Cameron. Ed Miliband really needs to find a way to energise and motivate his troops.
David Cameron has rung the Cabinet changes as he prepares to fight the next election. Here is an introduction to the figures on the rise.
It's not the first time Esther McVey has been tipped for a big promotion and missed out. Our Political Reporter Daniel Hewitt asks why.