Donald Macintyre's Sketch: Andrew Mitchell - the former Tank Regiment officer takes aim and fires

If, a few years ago, you had wanted to identify a future figurehead for all those fitted up by the police in the past, you could hardly have picked a more unlikely candidate than Andrew Mitchell – old Rugbeian, former Conservative Cabinet minister, Royal Tank Regiment officer and Lazards banker.

But that’s what made today’s press conference so electric. Sitting on a platform with his wife, his lawyer and his best friend in politics, David Davis – himself once a credible candidate to lead his party – Mr Mitchell insisted that while personally confident of eventual justice, he was speaking “on behalf of all those who may not have been able to fight back against police misconduct and have not had the support that I have had”.

The man who freely admits that he told officers who had refused to open the main gates of Downing Street to him and his bicycle: “I thought you guys were supposed to fucking help us” (“for which I subsequently apologised”) was pretty direct. The “incendiary fact” was that “armed police officers guarding officials in Downing Street have stitched up one of those they were supposed to be protecting.”

Rarely have words been less minced by a politician. He is prepared to give his version on oath in open court: “our intention”, he said, is to get PC Toby Rowland – the man who is supposed to have heard him use the word  “pleb” – to do the same.

At first sight the blurry images in the CCTV film of the 49 seconds Mr Mitchell took to get through the gate only confuse matters. Was this the “Plebgate ” equivalent of the Zapruder film and the grassy knoll – detonating half a century of unprovable speculation?

But as Mr Davis explained the images, there seemed at least to be a case to answer. Where were the several passers-by supposed to have witnessed the altercation? And how did he manage to say so much in such a short space of time?

On reflection perhaps only someone with Mr Mitchell’s credentials would have been prepared to confront the police and the CPS as he did yesterday.

He insisted he was speaking in “deep sorrow not in anger”. But his anger at the decision not only not to arrest PC Rowland, but not to interview him under caution, was palpable. The police will have learned at least one thing from yesterday’s press conference – Andrew Mitchell is not, in the well-worn phrase, going quietly.