After an unrepentant Mr Santer told a Brussels press conference he was "whiter than white", Mr Blair told the Commons that the Commission's response to Monday's highly critical report had been "wholly inadequate".
In an emergency statement on the biggest crisis in the EU's history, the Prime Minister said: "The President of the Commission should leave as soon as reasonably and practically possible."
During two hours of talks in Downing Street last night, Mr Blair urged Gerhard Schroder, the German Chancellor and holder of the European Union's rotating presidency, to seek fast-track agreement on a successor to Mr Santer at a summit of EU leaders in Berlin next week. But Mr Schroder warned that it could take longer to find an acceptable candidate.
The summit, which is due to agree a new EU funding system and reform the common agricultural policy, will now be overshadowed by the fiasco in Brussels.
Mr Blair believes the priority is to remove Mr Santer and install a successor who can drive through reforms to the EU. He opposes the idea of a caretaker president - such as Sir Leon Brittan, the Commission Vice- President - running the Commission until January, when Mr Santer's five- year term comes to an end.
Mr Blair said: "The new president must be a political heavyweight, capably of providing leadership and authority to the Commission." Downing Street refused to say whom Mr Blair was backing for the post, but he has publicly endorsed Romano Prodi, a former prime minister of Italy.
Privately, pro-EU British ministers fear the Brussels fiasco will harden British public opinion against the EU and joining the single currency.
But Mr Blair went on the offensive yesterday, presenting a paper to Mr Schroder proposing "root and branch reform" to the way the Commission operates, including a crackdown on fraud, financial mismanagement and what Downing Street called the "jobs-for-the-boys culture" in Brussels.
One minister said: "The door is now open to radical reform in Europe. It is an argument we can win if we are bold enough. Reform is the only way the EU can recover its credibility."
Earlier, in Brussels, Mr Schroder said he wanted "to take a decision rapidly", and hinted that Mr Santer's role as caretaker president will be short-lived.
That followed an angry press conference at which Mr Santer declared himself to be "whiter than white", and attacked the conclusions of the report as "unbalanced". Mr Santer and several fellow commissioners were furious about the final chapter to the 144-page document which accused them of failing to accept political responsibility for the culture of corruption. He said the conclusions were "totally unjustified" and "shameful".
"I cannot accept this affirmation that the Commission has been responsible for fraud, irregularities and mismanagement," he said.
Edith Cresson, the commissioner most seriously criticised, volunteered: "Perhaps I have been a little careless."
Colleagues and adversaries moved quickly to slap down Mr Santer. The President of the European Parliament, Jose Maria Gil-Robles, backed the inquiry findings and demanded a quick solution to the crisis. He said: "No one in our countries could imagine that a government which stands down because it doesn't have parliamentary confidence could stay in place for another nine months until another government is elected."
Even Sir Leon said: "I don't think this is the time to carp at the content or cavil at the wording of the report. It stands on its own merits."Reuse content