Norman Baker has quit as a Home Office minister, complaining that working under Home Secretary Theresa May was like "walking through mud". The Liberal Democrat MP accused the Tory Cabinet minister of viewing her coalition colleagues as "a cuckoo in the nest rather than part of government".
His decision comes days after he became embroiled in a fresh disagreement over drugs policy and accused the Tories of suppressing a report which backed his case for a review of the current law. "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," he told the Independent.
"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 has been helpful for the Government and the department. There comes a point when you don't want to carry on walking through mud and you want to release yourself from that."
Mr Baker's move to the Home Office from Transport in October last year was highly controversial as the MP had previously written a book claiming that David Kelly was murdered and the security services then staged a cover-up. But the Lib Dem leadership said they hoped it would ''sharpen our campaigning edge'' in a department where the two parties' views were often at odds over issues of civil liberties.
Deputy Prime Minister Nick Clegg expressed regret at the loss of "one of the most effective ministers" in the Government but said he "fully" understood why he was stepping down. In his formal resignation letter to the party leader, Mr Baker revealed that he had made clear in August that he was ready to quit - and pinned the blame squarely on his coalition colleagues.
"You will recognise that it has been particularly challenging being the only Lib Dem in the Home Office, which I see a newspaper the other day likened to being the only hippy at an Iron Maiden concert," he said. "Despite these challenges, I am pleased with what I have been able to achieve, not least to have been the first minister with responsibility for drugs to have put prejudice aside and published an evidence-based approach to this important issue, despite repeated Conservative efforts to block release."
He said he was also pleased to have spearheaded initiatives on female genital mutilation, anti-social behaviour and animal experiments. "However, in stark contrast to the Department for Transport, I regret that in the Home Office, the goodwill to work collegiately to take forward rational evidence-based policy has been in somewhat short supply.
"I have concluded, therefore, that for the time being at least, my time is better spent out of ministerial office." The part-time singer in a rock band also said he also wanted more time to devote to "my family and my outside interests, including my music".
In reply, Mr Clegg said his party colleague had done a "brilliant job". "However complex the issues have been, or challenging the coalition relations have proved to be, you have handled the political relationships within Government with great skill, always focusing on how to achieve liberal reform wherever you can," he said.
A Lib Dem spokesman said a replacement would be announced "in due course".
Mr Baker has made no secret of the "hostile" atmosphere within the Home Office - over issues such as drugs and the extent of state surveillance of communications - and his appointment reportedly left Mrs May ''spitting tacks''. Last week he was slapped down by Downing Street after claiming that a report "suppressed" by the Tories showed that locking up drug users was "nonsensical" and the case for reform overwhelming.
The coalition government row broke out after a Home Office study was published that showed treating drug possession as a health problem rather than a criminal matter has no impact on levels of substance misuse. "The reality is that this report has been sitting around for several months. I've been trying to get it out and I'm afraid that I believe that my my coalition colleagues who commissioned the report jointly don't like the independent conclusions it's reached," Mr Baker said.
In his final appearance at the despatch box in the role, he closed a Commons debate on drugs policy by telling MPs: "The genie is out of the bottle and it is not going back in. At the end of the debate I felt it had been a surreal debate and was I somehow in a parallel universe, where the House of Commons was behaving differently to how I thought it was going to behave," he told the Independent.
"I was hugely encouraged by spread of support for reform ... across the House." Talking about his decision to withdraw from his ongoing battles at the Home Office, he said: "I have always attempted to do things people don't expect. I think that's a good thing in politics.
"I don't regard ministerial office as the only worthwhile thing to do and I have never understood the mentality that says you have got to cling on as long as you can." And he gave an upbeat assessment of his party's chances of performing strongly at the 2015 general election, despite poor opinion poll ratings that regularly put its national support in single figures.
"I find that Conservative voters - not the hardline headbanger type, but the normal Conservative voters - actually like the Liberal Democrats in government. They think we have acted as an influence to stop extreme policies," he said.
"I think we will get credit for it. I think the polls continually underestimate our support and as the Labour Party veers off to the left to its comfort zone and the Tory party engages in a hopeless and pointless challenge to run after Ukip to the right, there's this huge space opening up in the middle for where I think the majority of the public are."