The fall of Patrick Mercer

Patrick Mercer ended his Westminster career with some panache yesterday, facing the cameras and admitting he was ashamed of his conduct, when he was filmed appearing to accept £4,000 to lobby for business interests in Fiji, in breach of Commons rules.

His performance was a reminder of his front-bench heyday as a media-savvy security expert, dispensing his military expertise with calm authority in many a studio.

For much of his time in Parliament, he seemed destined for a significant role in government as "minister for homeland security", at just below cabinet level, flitting between departments, co-ordinating anti-terrorism policy.

What went wrong?

I think the key factor in the fall of Patrick Mercer was the corrosive effect of disappointment. He entered Parliament as a high-flyer, a fast-rising military officer with an impressive record of service in Northern Ireland and Kosovo, who'd acquired serious media experience on Radio 4's Today programme.

After retaking Newark for the Conservatives, he was soon given, in the backwash of 9/11, a specially created shadow homeland security role by his then leader, Iain Duncan Smith.

He maintained it under Michael Howard, and was initially kept on by David Cameron, only to be sacked over remarks about the use of the term "black bastard" in the Army. If David Cameron had wanted to keep him, he could have done so, with a small expenditure of political capital; but Mercer was never a sympathiser.

He was closely identified with Cameron's leadership rival, David Davis, and had sounded off rather too loudly about the shortcomings of his new leader. So the leadership - which might never have given him the job in any event - had few qualms about dispensing with his services.

That highlights one of Mercer's weaknesses in Westminster terms; someone more marinated in politics would have kept their thoughts to themselves, or at least been more discreet. On the morning of the day he was sacked from the front bench, I bumped into him and we had coffee, after he'd done the rounds of Westminster studios.

He was fabulously and loudly indiscreet about his leader, to the point where I was slightly aghast. Hours later, and pretty much without warning, he was out. So Mercer became one of the Conservative irreconcileables, high on most lists of MPs likely to have sent a letter of "no confidence" in their leader to the 1922 Committee. And, denied the prospect of the career culmination he expected, he lost his way.

The Commons is full of people who think they should have been promoted, or not demoted, but few had the cup dashed from their lips quite as brutally as he. His was an extreme, but not isolated case.

A whole tranche of Tory frontbenchers were denied office because their party failed to win a majority and places in the coalition government went to Lib Dems. Some, not all, have sulked ever since. Similarly, there are a fair few Lib Dem ex-ministers who wander Westminster looking bruised, not to mention a number of Labour MPs who think they should be on the front bench team.

Plenty of MPs arrive at Westminster on a tremendous high, expecting the political world to tremble at their footsteps; then they discover it doesn't, and that they are anonymous foot soldiers.

Smart leaders try to find roles and massage egos. Gordon Brown had quite a penchant for appointing people as advisers on this and envoys to that. But ultimately the individuals concerned have to come to terms with thwarted ambition and carve out a role for themselves.

Because as the sad tale of Patrick Mercer demonstrates, there are plenty of ways in which they can get into trouble and do considerable collateral damage to Parliament if they don't.