Tory supporters were warned today the party still had a "mountain to climb" to win the next General Election.
As the Conservative conference got under way in Manchester, party chairman Eric Pickles said next year's poll was not "in the bag".
And he appealed directly to Labour, Liberal Democrat and trade union voters to come over to the Conservatives to secure victory.
"Join us. Trust us with your votes. Help us to change our country for the better," he said. "Give us your trust and we will never let you down."
At the opening session, Mr Pickles said the election campaign started now and chided those who thought it was in the bag.
"Take a tip from your Uncle Eric. It's just not going to be the case. Be under no illusion. The General Election is not in the bag.
"We still have a mountain to climb. To form the next government we need to take 117 seats. The Conservative Party hasn't done that since 1931.
"We need a swing greater than Margaret Thatcher managed in 1979."
Mr Pickles said the Tories were not prepared to sit back and watch Labour "implode".
The party planned to earn each and every vote. "We don't want to get people's votes just because we aren't new Labour. We want to earn people's votes because we want a mandate - a mandate for change."
He poured scorn on Labour's ministers, insisting: "You know Gordon Brown is in serious trouble when he recalls Peter Mandelson to the Cabinet and 12 months later he's still there."
Urging party supporters to show unity this week, he said the Conservatives must not be "deflected or distracted" from showing it was ready to bring change to the country as a whole.
Labour voters, who felt let down by the Government, should turn to the Tories - "a truly progressive party".
Liberal Democrats should also join the Tories - "a party with liberal democracy firmly at its heart".
Trade unionists too, who were worried about job losses and the neglect of thousands of young people, should vote Conservative - a party "determined to get Britain working again".Reuse content