Former Labour fundraiser and Middle East envoy Lord Levy this week dismissed Foreign Secretary David Miliband as a possible Labour leader.
Lord Levy told an audience on Sunday that Mr Miliband "doesn't have the gravitas or the stature to be a great leader of the Labour Party. But talk to me in five or 10 years' time and it might be different."
Lord Levy was in conversation with journalist, author and JC columnist Jonathan Freedland at the first Hackney Limmud event.
After talking about his childhood years in the area, he was asked by Mr Freedland what he thought of Gordon Brown.
Lord Levy replied: "It's very sad when someone wants something so desperately and when they get it they are unable to achieve what they want."
The political scene today was focused on presentation and "Gordon Brown is falling down on every front. I am sad because I don't want Labour to lose the next election. Have they screwed up on certain things? Yes, they have."
He said the party "needed to get its act together" to have any chance of winning the next election.
He concluded: "I don't see someone [in the party] who has that strength of appeal" to be a great leader.
Meanwhile, the Labour peer has teamed up with Stanley Fink, the former boss of Man Group, to make a comeback into the business world.
Lord Levy is to become chairman of International Standard Asset Management (ISAM), a London-based firm that trades in commodities. Mr Fink, who retired from Man Group plc - one of the world's leading alternative investment groups - in July after 21 years, will be chief executive. The move marks Lord Levy's first high-profile role since being cleared of any wrong-doing in the "cash for honours" inquiry in July 2007.
An accountant by profession, Lord Levy has built and sold several successful companies, notably the £10-million sale of Magnet Records to Warner Bros in 1988. "I am delighted to be involved with ISAM, and to be in business and work closely with Stanley Fink and all the team," he said this week.
Mr Fink, who will be responsible for the operational management, said he was "excited by the chance to build something significant at ISAM."