The document says that "the extent to which Tony is in control is beginning to worry the public".
It summarises its advice to the Labour leader as: "Tony in control, won't promise what we can't deliver; partnership with the people; trade unions, no favours...
"A problem for Labour is that of trust. This is Tony Blair's weakest rating and it seems to be more to do with a lack of clarity about what Labour will actually do rather than a real fear of Labour."
The findings from "focus group" polling by the party's advisers may have contributed to Mr Blair's determination to take a clear lead on Europe, in spite of the risk of losing votes to the Euro-sceptic approach by the Government.
The document, dated 6 March, also warned the Labour leadership against adopting a negative campaign to attack the Tories in the run-up to the election.
It said the feelings of hatred towards the Tories were declining and threats for a fifth term such as a privatised NHS and large class sizes had "no salience among floating voters - there are dangers in pursuing this line".
Too much negative imagery had the effect of depressing people when Labour's - and Mr Blair's - greatest strength was positive vision, according to the report leaked to the BBC Newsnight programme.Reuse content