"If it's not a constitutional treaty, so that it alters the basic relationship between Europe and the member states, then there isn't the same case for a referendum," Mr Blair said.
"We are going to get attacked whatever we do, but Europe needs to do it to move forward."
The prime minister added that he expects to agree a "basic outline agreement for a treaty" at the EU summit on June 21st to June 22nd, which is widely expected to be his last act on Europe while in office.
It will be left to the chancellor and Mr Blair's expected successor Gordon Brown to move forward with the outline. Asked what the chancellor's position was on Europe, Mr Blair said: "I think he is pro-Europe and pro-reform and he wants change in Europe - quite rightly."
An EU constitution, which included certain statehood clauses such as a flag and an anthem, was rejected by France and the Netherlands in 2005.
The June summit, which Mr Blair hopes will see an agreement over a slimmed down treaty, will be hosted in Germany by the chancellor Angela Merkel, who currently holds the rotating EU presidency.
Along with Ms Merkel, the prime minister sees the European Commission president Jose Manuel Barroso as a positive reformer within the EU.
He said: "Europe is moving in a reforming and changing direction and I think President Barroso has made a big difference."
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