It was either government or his band. And Norman Baker chose the band

Norman Baker said working with Theresa May was like "walking through mud". Credit: Reuters

Norman Baker is not not known for his conventional style so, true to form, his resignation letter is one of the more unusual that I have read in my time at Westminster.

Being a minister didn't give him enough time to play in his band.

The only Lib Dem in the Tory village (the Home Office) was a bit like being a cuckoo in the nest.

And working with the Conservative Home Secretary, Theresa May, was like walking through mud.

I detected not a sniff of remorse in Downing Street last night at Mr Baker's departure, which the Independent managed to keep under wraps until just before 10:30pm last night - surprising No10 as much as it surprised many at the Home Office.

The Home Secretary herself was known to have been angered when Nick Clegg shuffled Norman Baker into her department in the last Lib Dem reshuffle, so she is unlikely to miss her former ministerial colleague.

Meanwhile, her reputation with Tory backbenchers will be enhanced for making Lib Dem life so difficult in her department.

The Lib Dems too will be hoping the episode reinforces their differences with their Tory coalition partners as we enter the last few months before the general election (most recently exposed by their different approaches to drug prevention).

But the Lib Dems are not being consistent if they argue in one breath that coalition government works - and then, in another, seek to highlight how difficult it is for two parties to function together in the same government department.

Home Secretary Theresa May is not thought to have been happy with Baker's appointment in the first place. Credit: PA

Norman Baker has singled out Theresa May herself for criticism. Her style and her personality made coalition difficult in the Home Office - it wasn't like this, he wrote, in his previous ministerial job at the Department of Transport.

But there is another reason for his departure - and it's one with which other Lib Dem ministers will sympathise.

In Mr Baker's Sussex constituency of Lewes - he must see off a threat from the Conservatives if he still wants to be an MP after 2015 (and his is by no means the most marginal of Lib Dem seats).

That, he has concluded, is much easier to do when he is not burdened by the constraints of ministerial office.

And he can, of course, spend more time with his band.