Derbyshire Dales MP Sir Patrick McLoughlin has announced he is to retire at the general election.
The former Transport Secretary and Conservative Party chairman has been in Parliament for 33 years.
He said it had been an honour to represent the "beautiful constituency", but added: "I think it's time to let someone else have that opportunity."
The local Conservative association said the process of selecting a new candidate would begin immediately.
A former miner and local councillor, Mr McLoughlin first stood in an election in 1983 but only became an MP in a 1986 by-election.
He served under five Conservative prime ministers, in that time also being appointed chief whip and Chancellor of the Duchy of Lancaster.
He said: "There have been lots of highlights. The opening of the first part of the Ashbourne bypass, the many people I have helped and the four years as secretary of state for transport.
"I am lucky enough to represent one of the most beautiful constituencies in the country and I will miss it tremendously."
He added he would give his successor his full support but was was looking forward to spending time with his new granddaughter.