Yasmin Alibhai-Brown: This confrontation is a calamity for the capital

We could call it the "Bonfire of the Vanities", but that literary cliché feels glib for what is happening in the Metropolitan Police today. Two responsible, mature men, holding the most critical jobs in the capital, upon whose judgements and actions millions depend, bust up in public. We are witnessing scenes more poisonous than the McCartney/Mills divorce as the men get sucked up in a vortex of fury.

This confrontation is calamitous for Assistant Commissioner Tarique Ghaffur (a fellow Ugandan Asian) and for the Commissioner, Sir Ian Blair, who both endeavoured to transform and modernise the Met. Ghaffur is now receiving death threats, some from insiders he fears. The Deputy Commissioner Paul Stephenson orders him to "shut up" as if he is some coolie punkhawallah.

The fallout shatters the hopes of many of us who want to believe that inspirational leaders can make workplaces and institutions truly equal for all. However, the most catastrophic consequence is still to come. The collapse of trust between the two will cause fresh and wider fractures.

Countless British Asians, Muslims most of all, have already started to give up, turn against the nation they say will never give them their dignity and due. We who, in spite of relentless discrimination, want to keep the faith, find ourselves dismissed as pathetic suck-ups who never learn. The dangers of this disenchantment when we face the threat of terrorism should be obvious.

I know both men and I have never doubted their commitment to equality and diversity. Neither has ever had it easy – not within the force, nor outside. The right-wing papers always loathed Blair, and Ghaffur to them was an ethnic upstart. I have sat with them at dinners and observed them with a journalist's eye. They had a bond once, a unique comradeship, not between equals for sure – hierarchies are fixed in the force – but mutually respectful. The bombings in London brought new tensions but the duo remained connected and effective. Ghaffur stood by his boss when Ian Blair presided over the disastrous shoot-to-kill policy that led to the death of Jean Charles de Menezes and the armed raid on the blameless Muslim family in Forest Gate.

Ian Blair is not personally racist, that much I know. And Ghaffur is not an unctuous pleaser. Blair was the first Met Commissioner to take seriously Sir William Macpherson's findings into the death of Stephen Lawrence, unlike Sir John Stevens – much adored by rank and file. Paul Condon was contemptuous of the inquiry panel and the Lawrence family. Ghaffur rose fast through the ranks because he was an excellent strategist who planned operations brilliantly in volatile localities. He courageously confronted black crime and Muslim militancy.

Neither men, however, is beyond criticism. In spite of millions being spent on facile training courses, racism has not been stamped out in the Met. Sexism is alive and kicking too. During Blair's watch, there have been serious cases of proven racism by Met staff. Gurpal Virdi, an honest man and good copper, won two cases of discrimination against the Met and the flamboyant Ali Dizaei was wrongly accused of a number of offences and cleared by a jury in 2003. Ghaffur now complains more robustly about this racial discrimination, but on his own behalf. Racism is a grave violation of human rights and charges of discrimination should never be devalued or used for personal gain. Was it ever thus for him? And did he just put up with it until he could no more? If so, Blair has a case to answer. If not, Ghaffur may regret he instigated the action.

Last week, I talked to coppers of every description across the country. Very few, I have to say, understand why Ghaffur has turned. Black and Asian officers asked how he could have got to be Assistant Commissioner if he was facing the discrimination he describes. One, a Muslim, said: "I respect the guy. But he's had it good, easy even. They pushed him. Blair did. He should come here if he wants to see real racism. People like us have no chance to move up."

White interviewees of low rank were not only cross, they wanted no more "this diversity rubbish, bending over backwards". Blair came in for a kicking too – too PC, got his just desserts, hopeless, should be sacked.

The two pioneers can never work together again. Black and Asian officers will not expect to nor be encouraged to go for the top. Recruitment into the forces will get harder, intelligence from Muslim enclaves will dry up. London will be more vulnerable as a result. Oh the pity of it all.