Conservative leader Michael Howard has launched his programme for government with a strong attack on Tony Blair.
The Tory leader said at 63 he could hang up his boots and enjoy his retirement but he wanted to "battle for Britain", the country he loved.
Mr Howard urged people to read the Tory manifesto and "see how we've changed". He warned that re-electing Labour would mean "five more years of smirking".
Earlier Mr Blair attacked the "flawed" Tory plans for the economy.
Lib Dem leader Charles Kennedy had to cancel plans to campaign in Devon to be with heavily pregnant wife Sarah, who has been taken into hospital.
His party have now postponed their manifesto launch which had been planned for Tuesday and deputy leader Sir Menzies Campbell is taking over his engagements.
Mr Howard, the first of the main party leaders to launch his election manifesto, said: "It is time for change, it is time for action."
He said the manifesto was purposely thin so people would actually read it.
"You don't have to settle for second best - your vote can change things," said Mr Howard.
"If you long for cleaner hospitals, more police, school discipline, controlled immigration, lower taxes and accountability - you can vote for it, on 5 May.
"On 5 May you can bring an end to the years of let-down, and start sorting out the things that matter.
"On 5 May you can let the sunshine of hope break through the clouds of disappointment we all feel."
The Tory leader went on from the launch in London to unveil policies for Scotland and Wales in Glasgow and Cardiff.
Labour also unveiled part of their manifesto, focusing on their plans for education and a six point pledge card for the economy.
The Lib Dems also outlined their plans to recruit 21,000 more teachers to provide smaller primary school classes.
Monday was the first official day of campaigning as the Queen formally dissolved Parliament - meaning there are no longer any MPs, although ministers retain their government roles.
The Tories' manifesto does not include the further details of plans for tax cuts. Those will be held back until later in the campaign.
In the manifesto, Mr Howard promises voters greater control over their money and greater choice in public services. He says the Tories offer "action" not Labour's talk.
Mr Blair and Gordon Brown are continuing their joint campaigning and fronted Labour's first election rally on Monday evening, as part of a two-day national tour.
At the event in Oldham, Mr Blair said the Tory manifesto was not just "threadbare" but was based on fear rather than hope.
Earlier, Labour's election co-ordinator Alan Milburn called the Tory manifesto a "fraudulent prospectus" that was "full of holes".
"This is a new manifesto from the same old Tories," he said. "It confirms they still stand for privilege not opportunity in our country."
For the Lib Dems, Mr Kennedy said: "People have already decided that they do not want the Conservatives back running health and education.
"They also know that Conservative pledges to put money back into public services at the same time as cutting taxes and borrowing are simply not credible."