Britain’s most senior Asian officer will announce formal legal proceedings this week against Sir Ian Blair, the Metropolitan Police Commissioner, alleging racial discrimination at Scotland Yard.

Within the next few days lawyers acting for Assistant Commissioner Tarique Ghaffur will lodge papers that claim he was subjected to a catalogue of victimisation, bullying and harassment. Some of the allegations are said to refer directly to the actions of the commissioner.

A large part of the claim – up to 30 per cent – will be about allegations that Mr Ghaffur was illegally bugged and put under surveillance. The papers allege that he had hundreds of his telephone calls tapped and that Mr Ghaffur – codenamed Vivaldi – was “the subject of direct surveillance . . . This was a direct attack on his honesty and integrity.”

Although the primary target of the operation was another officer – Chief Superintendent Ali Dizaei, who was codenamed Mozart – Mr Ghaffur is claiming that he was also targeted and not just caught up in that operation.

The papers allege that Mr Ghaffur was photographed at more than 30 meetings with another officer at restaurants and cafés in London. The operation was codenamed Helios. Ian Blair, then deputy commissioner, was nominally in charge. It collapsed after four years, leaving taxpayers with a bill of £4 million. Mr Dizaei was cleared of perverting the course of justice and fiddling his expenses.

A source close to Mr Ghaffur said that the attachment of a codename to the assistant commissioner was enough to suggest that he was specifically targeted.

“It is a massive claim with around 70 allegations involving a whole host of issues,” he said.

The source told The Times that Mr Ghaffur was so angry about the way in which he had been treated that he had decided to “press the nuclear button”. He had consulted the National Black Police Association before going ahead with his legal action.

Sir Ian faces further pressure from an inquiry carried out by Sir Ronnie Flanagan, the Chief Inspector of Constabulary, who is examining the award of Scotland Yard contracts to Impact Plus, a consultancy that was run until last year by Andy Miller, 54, who has known Sir Ian for 30 years and accompanied him on skiing trips.

Sir Ian has denied any impropriety in his relationship with Mr Miller. He informed the force and the Metropolitan Police Authority of his friendship with the businessman in November 2002 and says that he has been open and straightforward.

Next month an inquest into the shooting of Jean Charles de Menezes at Stockwell Tube station in 2005 is expected to expose serious failures within the Met. Scotland Yard is also awaiting the outcome of an employment tribunal involving Commander Shabir Hussain, who has accused the embattled police leader of passing him over for promotion because “my face did not fit and did not fit because I am not white”.

Mr Hussain, 45, has told the tribunal that he was rejected four times for promotion to deputy assistant commissioner while Sir Ian’s “favourite sons and daughters” succeeded after one or two attempts. He claims that he was ignored for promotion even when he was more experienced and better qualified than other candidates.

A spokeswoman for Scotland Yard, responding to claims about Mr Ghaffur’s case, said: “Any matter that AC Ghaffur intends to raise in his suggested employment tribunal claim should be dealt with through the proper channels – where both sides can be fully and carefully considered – and not through stories leaked or placed in the media.”

Explore Law

• Corporate Law

• Public Law

• Columnists

• Law Panel

• Student Law

• Law Reports

Times Recommends

• Future Stars of the Bar 2008
• Lawyer of the Week: Julie Morris
• Charging suspects - why it's a job for prosecutors