But Mercer, alas, is not expected to join the government. His political career path is something of a tragedy. He rose to the top at the Sherwood Foresters, his father's wartime regiment, and did so much to encourage ethnic minorities that the BBC came and made a film about his battalion: the way he treated his men, with no special favours, was an exemplar of equal opportunity in action. Then he was sacked by Cameron for explaining the details of his policy to a journalist - that equality means ethnicity is picked on by soldiers as much as being fat or ginger, and that he "came across a lot of ethnic minority soldiers who were idle and useless, but who used racism as cover for their misdemeanours".
To command a battalion in Bosnia, as he did, takes certain skills. To navigate your way through the warped world of politics requires different skills - and ones that Mercer was not over-endowed with when he entered parliament. I mean this as a compliment. Quite often you see people (like Archie Norman) who accomplished great things in the outside world, but who just don't shine in Westminster. Flair, hard work and ingenuity don't always count for much. Tribalism, schmoozing and self-promotion tend to be the skills needed in politics. To the MPs who have been in politics most of their adult lives, any conversation about race set alarm bells ringing instantly. To Mercer, the equality agenda was one he enacted, not opined about. He had five company sergeant majors who were all black. With such a record, it would never enter his head that he'd be called a racist.
"Wrong choice of career Mr Mercer. Surely you did not expect to get away with straight talking in Westminster? Its not the army you know."
Genuinely promoting equality in the military takes a very different form to promoting it in Westminster. Mercer should have known this, but his political nodes were not sufficiently well-developed. Ditto when he agreed to advise Lord West - he didn't realise it would be billed by Brown as a defection (as opposed to Bercow, who has no excuse). Now, as chair of the counter-terrorism commitee, Mercer is beginning to shine again. And the way he brags about the sex scenes in his forthcoming novel does hint of a man who is not prenning himself for government and may instead make a career in the backbenches. If so, this may be no bad thing - for him or Parliament. The atrophying of Parliament has been a depressing theme under Labour, and having robust select committee chairs could revive it. Mercer may have no frontbench job, but he's a major asset to the party. So let's see far more of him.