LONDON, England (CNN) -- British police warned on Monday that officers were preparing for a "summer of rage" as protests mount across Europe against the economic crisis.
Protesters march in Dublin angry over the government's handling of the economy.
David Hartshorn, who heads the Metropolitan Police's public order branch, said growing unemployment, failing companies and the recession could spark a "mass protest."
Until now, Superintendent Hartshorn said, there were insufficient numbers of activists to carry out large-scale demonstrations, but he told the Guardian: "Obviously the downturn in the economy, unemployment, repossessions, changes that. Suddenly there is the opportunity for people to mass protest."
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"We've got G-20 coming and I think that is being advertised on some of the sites as the highlight of what they see as a 'summer of rage,'" he said.
The officer added that protesters may target banks, especially those still paying large bonuses despite receiving state aid.
Protests sparked by the economic crisis have taken place recently in several cities across Europe. More than 100,000 people marched in Dublin on Saturday over the Irish government's handling of the recession. Similar large demonstrations have also broken out in France, Greece, Iceland and Russia.
And in Britain hundreds of oil refinery and power station workers joined strikes over the use of foreign workers.
Despite his "British jobs for British workers" pledge at the Labour party conference in 2007, British Prime Minister Gordon Brown described the unofficial strikes as "counter-productive."
Speaking from the World Economic Forum in Davos, Switzerland, Brown said he understood why people were worried: "They look round and say, well, why can't we do these jobs ourselves."
However he said instead of spontaneous strike action, "what we've got to do over time, as I've always said, is that where there are jobs in this country, we need people with the skills, developed in this country."