In its heyday, the organisation numbered around 1,000 volunteers in New York, mostly young men who night and day patrolled the most perilous corners of the city, above and below ground. Today, the Angels' New York membership has dwindled to 125; much of their time is spent appealing for funds on street corners. The only bright spot is in activities abroad, where the Angels continue to add new chapters, most recently in Moscow and Tokyo.
Now, the Angels, founded in 1979 by a Bronx McDonald's manager, Curtis Sliwa, are about to lose their headquarters of the past seven years, a rent-free shopfront in the Hell's Kitchen neighbourhood of Manhattan, west of the theatre district on 46th Street. The state, which owns the building, plans to convert it into housing for the homeless, and the Angels have until 1 January to get out. They have nowhere to go.
Mr Sliwa, 41, reckons that the Angels are the victims of their own success. When they were invited by a group of restaurant owners to set up in Hell's Kitchen in 1988, it was to "wage a war against the drug dealers and the pimps and the hustlers who had laid siege to the area and turned Eighth Avenue into the Green Line of Beirut". Now the neighbourhood is largely secure again and the restaurants, which once were shuttering up, are thriving.
Moreover, as crime across New York City declines, so the public support for the Angels is bound to recede. Mr Sliwa says he welcomes the change and credits the city's Republican mayor, Rudolph Giuliani, for tackling crime aggressively. "People feel a lot safer going on the subway than they used to. Your chances of getting mugged have decreased substantially."
As to why fewer volunteers are attracted to his group than before, Mr Sliwa says it is because of the obvious dangers involved. Over the years, five Angels have died in New York and several dozen have been injured. "People would rather go to Bosnia and join peace-keeping than join the front line of the war against criminals," he suggests.
Abroad, though, the Angels' uniform - the beret, white T-shirt and jackboots - is becoming more commonplace. Altogether there are 47 chapters worldwide, with two in Britain - in Stoke Newington, north London, and Manchester. Tokyo, which was terrorised by the subway gas attack last spring, is the latest addition. All the chapters send volunteers to New York for training.
Mr Sliwa says he is confident that new accommodation will come his way, even if it is not in Manhattan but in another borough: "This is just another setback, but we will move forward." He notes that his group's most generous benefactor over the years is not a New Yorker, or even an American. That honour goes to the British film director, Michael Winner.