More than a third of voters believe the Army will have to be brought in to deal with a "summer of rage" on British streets as the recession bites, a poll showed.
The widespread fear of serious unrest was disclosed as a senior police officer warned activists were planning unrest and could find rioters easier to recruit because of the credit crunch.
Superintendent David Hartshorn, who heads the Metropolitan Police's public order branch, said known activists were planning a return to the streets centred on April's G20 summit of world leaders in London.
And intelligence shows they may be able to call on more "footsoldiers" than normal due to the unprecedented conditions - which have led to youth violence in Greece and mass protests elsewhere in Europe.
YouGov polling for Prospect magazine found 37% thought such "serious social unrest in several British cities" was certain or likely - although a slim majority (51%) disagreed.
Almost three quarters (73%) said they feared a sustained return to mass unemployment.
And a clear majority (64%) also favoured forcing the under-25s to do a year of full-time, modestly-paid community service such as working with the sick and elderly or helping with environmental projects.
Labour MP Frank Field told Prospect the main political parties should join forces to develop the idea. He said: "The time has come to look at this idea. A new bipartisan commission should be established to look into how it could be done, perhaps led by figures as respected as David Blunkett or David Davis."
Although the biggest support for a compulsory scheme was among the older generations, a majority of 18-30 year olds (52%) also gave it their backing.
Gordon Brown's spokesman said: "The Prime Minister's view on this is that of course he understands people's concerns and he also understands that people are angry, for example about the behaviour of some of the banks. That's why he is absolutely determined that the Government does everything possible to deal with those concerns and help people and businesses get through what is a global recession."
