The prime minister travelled to Buckingham Palace to ask the Queen to dissolve parliament on 12 April.
The contest for the 650 seats is likely to be the toughest since 1992, when John Major’s Conservatives defeated Neil Kinnock’s Labour party, and a hung parliament is a real possibility.
Announcing the date outside No 10 Downing Street, Brown said he would seek to regain the trust of the British people in politicians.
He also promised to protect public services and emphasized the importance of "fairness for all".
On the economy he said: "Over the next few weeks I will go round the country - the length and breadth of our land - and I will take to the people a very straightforward and clear message - Britain is on the road to recovery and nothing we do should put that recovery at risk."
And in a final rallying call he said: "Let's get to it".
A YouGov poll for the Sun last night put support for the Tories above 40 per cent for the first time since 7 January. It put the Tories at 41 per cent, Labour at 31 per cent and the Liberal Democrats at 18 per cent. However, an ICM poll for today’s Guardian puts the Tories just four points ahead.
Conservative leader David Cameron said his party would champion "the great ignored", saying: "They’re the people of Britain and they just want a reason to believe that anything is still possible in our country."