The ruling executive of the UUP
approved the leader's recommendation at a meeting in an east Belfast hotel.
Out of the 105 votes cast, a total of 88 were in support of the move, with only the UUP
As Sir Reg served his first full day as leader of the UUP
, Mr Ahern said the politician's experience and political ability well-qualified him for the new role.
It was a final act of defiance to the UUP
leadership, which began when he walked out of final negotiations for the Good Friday Agreement in April 1998.
Sources said the Lagan Valley MP, who had been touted as a possible leadership challenger, will join UUP
leader David Trimble and Stormont minister Michael McGimpsey at crucial peace process talks involving Tony Blair, Irish Premier Bertie Ahern, the nationalist SDLP and Sinn Fein.
After the Democratic Unionists emerged as the largest party in 2011 with 38 seats and the UUP
came third on 16, a huge electoral turnaround would be required for Mr Nesbitt to emerge victorious on May 5, particu-larly as the party is only fielding 33 candidates.
The move by the UUP
means the debate in Northern Ireland will not divide along traditional orange/green lines.
The former MP said the UUP
was now ready to play a full part in the BIIPB, which officially changed its name to the British-Irish Parliamentary Assembly to accommodate unionist concerns.
"I wouldn't involve myself in choosing a leader for the UUP
"Whatever we come up with has got to be real," said the UUP
He also announced that the UUP
will hold a special meeting to discuss the report by Chris Patten's Commission on Policing after it is published.
During numerous interviews one UUP
spokesman after another has had their inconsistencies exposed.