David Cameron said in five years he had put Britain "back on her feet again" as he formally fired the starting gun on the election race after a meeting with the Queen.
Speaking on the steps of Number 10 after returning from Buckingham Palace where he asked the Queen to dissolve Parliament, Mr Cameron said voters face a "stark choice" between him and Ed Miliband.
With 38 days to go until the election, the Conservatives would offer strong leadership and a country that was safe and secure but Mr Miliband would offer a country mired in "economic chaos".
He said: "Britain is on the right track. This election is about moving forward, and that is what, as Prime Minister here at Downing Street, I will deliver."
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And he warned that if voters put Mr Miliband in Number 10 working families would face a £3,000 tax hike.
In a YouTube video released by the Conservatives before Mr Cameron's journey to Buckingham Palace, the leader said 7 May was "the most important General Election in a generation".
Deputy Prime Minister Nick Clegg also made the trip to Buckingham Palace for a meeting with the Queen in his role as President of the Privy Council.
Speaking ahead of the meeting Mr Clegg predicted another coalition government come 7 May and said: "It is my view that the era of single-party government is now over in British politics."
"About the very last thing the country now needs is a lurch to the left or the right and yet that is exactly what the Conservative and Labour parties are now threatening."
He added: "I think what the vast majority of people in this country want is that we keep this country and our government anchored in the centre ground, which is where the Liberal Democrats have anchored the government over the last five years."
The final act of pomp and ceremony of the coalition government fires the starting gun on the General Election campaign.
As the formalities played out at Buckingham Palace, Ed Miliband was attempting to win over business with the launch of its first "mini manifestos" in which the Labour leader warned of the "clear and present danger" of leaving the EU.
He said: "There could be nothing worse for our country or for our great exporting businesses than playing political games with our membership of the EU. David Cameron used to understand that. But in the past five years our place in the European Union has become less and less secure."
UKIP leader Nigel Farage was due to launch his party's five election pledges this afternoon along with a new poster.
The pledges are: "1. Say No to EU 2. Control our borders 3. Extra £3bn for the NHS 4. Cut foreign aid spending 5. No tax on the minimum wage."
With Parliament dissolved, MPs immediately lose their title and are asked to remove references to it, or place disclaimers on any email or social media account which names them as an MP.
It has already prompted a Twitter squabble with the Conservative parliamentary candidate for Worsley and Eccles South posting: "I'm sure it's an oversight that my Labour opponent's Twitter name now breaches Parliamentary rules after dissolution."
Some, including Conservative MP Maria Miller, were refusing to remove the MP on their accounts. Ms Miller argued the Twitter account was set up before dissolution.
MPs elected in 2010 will also find their parliamentary pass for Westminster Palace ceases to work.
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