High-profile US "supercop" Bill Bratton has confirmed that he would be interested in leading the Metropolitan Police if he was allowed to apply.
It is widely thought that Prime Minister David Cameron had Mr Bratton in mind when he told Parliament last month that police recruitment procedures should be changed to allow candidates from overseas to apply for top jobs.
But Home Secretary Theresa May appears to have blocked any chance of him succeeding Sir Paul Stephenson as Met commissioner by insisting that only British nationals will be considered for the post.
A job advert placed by the Home Office and Metropolitan Police Authority states that candidates "must be British citizens". The Home Secretary has the power to appoint the new commissioner, after consulting with London Mayor Boris Johnson.
Mr Bratton, who won fame with his "zero tolerance" policies as police chief in Boston, New York and Los Angeles, said he understood the decision to reserve the UK's top police job for British nationals was taken unilaterally by Mrs May.
He said that it ruled out not only him but also many high-calibre potential applicants from Canada and other parts of the Commonwealth.
Mr Bratton told the US-based Daily Beast news website: "From my perspective, I have been interested in looking at that position, if it was open to people outside of Great Britain.
"It's one of the most prestigious positions in democratic policing in the world.
"I've had a long, almost 20-year affiliation with England, with the Met, and their role in democratic policing. I don't know that there's a major police chief in America or Canada, or for that matter in the British Commonwealth, who, given the opportunity, would not consider it."
The 63-year-old, currently chairman of the Kroll private security firm, said the decision to consider only British applicants "was apparently a unilateral decision, and it's never been determined if it was in consultation with the Mayor of London...
