Recently in this column, I wrote in support of Ian Blair, Commissioner of the Metropolitan Police, for his courageous pursuit of those officers within his organisation who continue to practise racial discrimination in the course of duty. Now I am in swift retreat, hotly pursued by the undeniable facts which contradict his version of events surrounding the execution of Jean Charles de Menezes. Long will I remember his words after the killing: "As I understand the situation, the man was challenged and refused to obey police instructions." As far as he was concerned, Londoners had been saved from another suicide bomber.

Only a viciously authoritarian state with a slothful population in tow would not question Ian Blair's authority in such circumstances. Much more followed, as we know. The demonisation of the victim was intense. His "Mongolian eyes", his puffa jacket, his illegal immigration status, all trickled on to the pages of the newspapers.

And then there was the disappearance of the CCTV tapes from Stockwell Tube station, the challenge to the Independent Police Complaints Commission, the surveillance officer who was pissing in the wind at the moment when he could have seen that this Brazilian was no East African.

The IPCC cannot bear the weight of the required investigation. Its brief is too narrow. Only a public inquiry could do the case justice.

And please, let us bring to an end the demonisation of Asad Rehman and Yasmin Khan, activists in the campaign for justice for the young Brazilian and his family. Both are from the Asian community, bright, educated citizens who can draw on the experience of dissent that has enriched British society for centuries. Had they gone off to the City to make millions for some investment bank, they would be praised as successful. That they have used their talents to advance a cause of the left is as British as the Labour Party, and ought to be commended.