The Liberal Democrat leader also claimed in an interview on GMTV that over the past five years his party had moved "from a party of protest to a party of government."
He said the Liberal Democrats had beaten the Conservatives into third place in local government and, as for Labour, he said: "What does Labour stand for any longer? Mr Blair may know, but I'm afraid I don't, and many people don't either. They seem to be as close to the Tory party as possible ...
"Vote Labour on Thursday, Mr Blair gets to Downing Street, you change the name on the door-plate, but not a penny extra goes into your school or hospital."
Mr Ashdown's rejection of the tactical vote against the Tories was maintained on the BBC Election Call programme.
"What is politics about?" he asked. "What are elections about? Elections are about voting for what you believe in. If you don't vote for it you are not going to get it.
"Our job - Mr Blair, Mr Major, myself - is to put forward clearly to the British people ... what it is we stand for, and let people choose what they want to do according to what their priorities are.
"I think that is relying on an intelligent vote from intelligent people without pushing people around.
"I am inviting people to vote Liberal Democrat and that's the only way you get the things only we now stand for. Unhappily now, with Labour offering the same policies as the Conservatives, if Labour should be elected it would not make any difference."
Without hearing that contemptuous view, Mr Blair told the day's election press conference that there was no question of any deals being done with the Liberal Democrats after Thursday.
"I am in favour of co-operating with other parties where it is in the national interest to do so," the Labour leader said. "But I am not talking pacts, deals and all the rest of it - that's not on the agenda and never has been."
Mr Ashdown told Election Call: "The proposition being put equally by the Conservatives and Labour is to make two impossible promises.
"Promise number one is that in the present economic climate that you can cut taxes and promise number two is that you can maintain public services. They must tell us which of those two promises they intend to break after the election, because they are unachievable."
Mr Ashdown said: "If you want to go on actually having elections based on lies, on tax promises that are betrayed straight afterwards ... vote Labour, vote Conservative, it's not going to make any difference, we won't make the long-term investments ... and we will have a system of politics which continues to decline in respect because politicians make promises which simply can't be believed and they betray straight after the election."Reuse content