Norman Baker, the Liberal Democrat crime reduction minister, has resigned from government and cited his strained relationship with the Conservative Home Secretary Theresa May as the main reason.
In an exclusive interview with the Independent, the MP said his year working in the Home Office was like "walking through mud".
They have looked upon it as a Conservative department in a Conservative government, whereas in my view it’s a Coalition department in a Coalition government.
That mindset has framed things, which means I have had to work very much harder to get things done even where they are what the Home Secretary agrees with and where it’s been helpful for the government and the department.
- Norman Baker
In a letter to the MP, Lib Dem leader Nick Clegg said: "You have proved yourself as one of the most effective ministers in Government: always determined to deliver a more liberal agenda for Britain...
"I very much hope that if the Liberal Democrats are in Government after the next election, you will once again make yourself available for Ministerial office."
Mr Baker, who will continue in his role as an MP for Lewes in East Sussex, said of Theresa May:
I think she is quite competent and professional, and I have a lot of respect for her professionally.
I just think it’s a pity that she took the mindset that the Lib Dems had to be put up with, and we were almost a cuckoo in the nest rather than part of Government.
One of the key factors in his strained relationship with his Conservative colleagues was their respective views on drugs policy. Mr Baker was a vocal supporter for reform, with his last speech in the House of Commons last week addressing a report that suggested punitive measures for dealing with drug abuse are not working.
"If anyone is soft on drugs, it's my Conservative colleagues, because they are the ones who allow the process to go on whereby drug dealers continue to make money and people continue to get fined and carry on taking drugs," he said.