The Tory peer, and David Cameron's adviser on growth, said offering a referendum on EU membership would be a "punt" that would "drive away inward investment".
Their intervention was welcomed by the Labour peer Lord Morris of Manchester - the parliamentary adviser to the Royal British Legion and a long-time campaigner on behalf of the Gulf veterans.
Conservative peer Lord Blackwell, who was a political adviser to former Prime Minister John Major, said that "the primary reason for our current deficit" was a growth in public spending from 40% of GDP to closer to 50% over the last decade.