The endorsement for Mr Blair came from Lord Sterling, chairman of P&O, as he returned from a trade mission to the Middle East with the Prime Minister.
Lord Sterling, awarded a life peerage in 1990 in the resignation honours list by Lady Thatcher, made it clear he would be willing to work with a "sensible" Labour government and that other leading businessmen felt the same.
The vote of confidence in Mr Blair's leadership by some of Britain's top industrialists will give Labour credibility as it seeks to win the confidence of the City for Labour's economic strategy.
Lord Sterling was not suggesting he had abandoned support for the Conservative government. "I have supported the policies of this government over the last 15 years because they have created a much better climate for business." He added: "Any sensible government that looks after our interests, we would work with them."
His company has been one of the main corporate contributors to Conservative Party funds over the last decade.