Patricia Hewitt will tell British businessmen today that Tony Blair is planning to "hit the ground running" after the election with a campaign to secure a "yes" vote in the referendum on the European constitution.

The trade and industry secretary told the Independent, in advance of her annual Mansion House speech: "The starting point is a recognition that there has been quite a shift in mood among the business community in the last four or five years.

"A lot of business people who were pretty pro-European some years back are increasingly sceptical."