Mark Hughes: Another scandal facing firearms unit tarnished by Menezes death

While the alleged actions of the officer known as "AZ8" are, for the time being, confined to him alone, they do nothing to help improve the already tarnished image of the CO19 firearms unit. The team comprises some of the most highly trained armed officers in the UK, but has faced criticism in the past, most notably the killings of Jean Charles de Menezes, a commuter mistaken for a terrorist, and Harry Stanley, who was shot dead while carrying a table-leg which officers mistook for a shotgun.

During the De Menezes inquest, officers were portrayed as men who had decided to kill the Brazilian before even entering the London Underground station and were later described as "trigger-happy" by Boris Johnson.

In the Saunders inquest, the officers were criticised more for their lack of organisation than their apparent eagerness to open fire. But the latest allegation is one which has been levelled at CO19 officers before. In the De Menezes case Michael Mansfield accused one of the firearms officers of repeating phrases he had heard another say during his evidence.