By Steven Shukor BBC News, London

Mr Dizaei says he is not bitter and twisted by his experience

He is, by his own admission, "flash, combative and arrogant", dines at the Ivy, prefers nightclubs to pubs and enjoys the limelight.

The Iranian-born officer is just emerging from a media storm whipped up by the serialisation in a newspaper of his controversial autobiography, Not One of Us.

In it, the chief superintendent lays into a handful of Metropolitan Police officers who he believes were hell-bent on destroying his reputation and career.

The book centres on the two-year, multi-million-pound corruption investigation, Operation Helios, launched against him in 1999.

Mr Dizaei was publicly accused of being involved in drugs, having contact with prostitutes, spying for Iran and corruption.

I don't regret writing the book... I needed to tell my version of events Ali Dizaei

He says the allegations, including some such as accepting a free calendar, proved to be completely and ridiculously unfounded.

He has accepted in some areas his conduct fell "far below the standards expected of a police officer" - such as when he threatened to ruin the reputation of a former girlfriend and her family.

He also made a false report about damage to his BMW car in September 2000 - for which he eventually stood trial.

Mr Dizaei, 44, said he lied about where he had left the car because he did not want his boss to know he had attended a Black Police Association (BPA) meeting.

He was cleared with perverting the course of justice and misconduct in public office at the Old Bailey in 2003.

"The book was my opportunity to say I'm not 'the cocaine-snorting petty criminal spying for Iran' they portrayed me to be," says Mr Dizaei.

The BBC News website has learned his publishers are in talks with eight film companies interested in buying the rights to the book.

"Most are looking to do a docu-drama," said Rebecca Grey, from Mr Dizaei's publisher's Serpent's Tail.

Cowboy boots

The foreboding whistle from The Good, The Bad and The Ugly suddenly peels out and interrupts our conversation.

"Sorry," says Mr Dizaei, as he answers his mobile phone.

The theme song from the Clint Eastwood spaghetti western classic is a reminder of his penchant for the flamboyant.

But gone are the sunglasses, designer belt or cowboy boots, he was wont to wear with his uniform - which once riled his more conservative colleagues.

I'm very happy in my job. I won't internalise this bitterness and let it affect my job Ali Dizaei

Proudly wearing his Metropolitan Police uniform, Mr Dizaei speaks of his passion for the job and his determination to continue his fight for a more diverse police force.

He says he was disappointed by his failure to win promotion to the rank of commander last week and accepts the book may have been a factor.

"I can't rule out bad timing," he says. "But I'm waiting for my formal feedback to understand the decision.

"My performance as an individual leading a borough was assessed by my supervisor as exceptional for two successive years."

Hounslow in west London, where he is borough commander, has seen crime fall by 6.1% and detection rates rise to 21.6% in the last year, meeting the Met's annual targets.

"I don't regret writing the book," he says. "One's beliefs and values should occasionally supersede one's career aspirations. I needed to tell my version of events."

'Not bitter'

While Mr Dizaei says the feedback for the book has been on the whole positive, with many emails lauding his courage, it is by no means unanimous.

An Asian detective sergeant based at Scotland Yard told the BBC News website: "Internally, in the [Met], Ali Dizaei is perceived to be very unprofessional and only out to make money."

Mr Dizaei says he intends to use the proceeds from the book to set up a university scholarship programme for deprived young people with the Black Police Association (BPA).

He will also be keeping some of the earnings in reserve to pay for his own costs and possible future libel action in relation to media reports of his case.

Apart from bringing closure to a difficult chapter of his life, Mr Dizaei, who also acts as a legal advisor for the BPA, hopes the book will "invigorate" the Met's diversity programme.

"The force has made huge inroads but it still doesn't reflect the society we serve," he says.

"Diversity is not a beauty contest, it's an operational imperative. In a few years half of London will look like me or close enough."

In Not One Of Us, Mr Dizaei writes of his desire to see all those who put him through his ordeal held to account.

"Not every one has paid," he says. "Many of them have been promoted. But I'm not bitter and twisted.

"I'm very happy in my job. I won't internalise this bitterness and let it affect my job. If I did, it would be a victory for my enemies."