Mr Robinson, deputy leader of the DUP for 28 years, said that he was deeply honoured to have been chosen by Assembly colleagues to take over from Mr Paisley.

The revelation came on the day Mr Robinson, the Stormont Finance Minister, met with the Irish Finance Minister Brian Cowen - who is also the Taoiseach-elect - in Belfast for a major jobs announcement.

However, it could be June before he becomes Northern Ireland's First Minister.

Mr Paisley will resign in May, triggering the removal of Martin McGuinness as Deputy First Minister.

Mr Robinson last night hinted at a move away from the jovial imagery which led to Ian Paisley and Mr McGuinness acquiring the nickname in government of the Chuckle Brothers.

"Obviously, within the Executive I work on a regular basis with the Deputy First Minister," he said.

"We will do business together in a professional and workmanlike way and hopefully in a productive way that will bring results."

The East Belfast MP will be formally declared DUP leader at a meeting of the party's 120-member executive on Thursday night in the offices of Castlereagh Borough Council in Belfast.