Sinn Fein wanted tonight's television debate with the Ulster Unionist Party to be a "positive engagement", a party spokesman said. Senior UUP sources said most of their supporters felt it was right to "take on" Sinn Fein.
The debate between the UUP security spokesman, Mr Ken Maginnis, and the Sinn Fein chief negotiator, Mr Martin McGuinness, will be broadcast live from Belfast during Newsnight tonight on BBC2.
A Sinn Fein spokesman said: "In recent weeks, we have made a very strong case for unionist involvement in the talks. Martin McGuinness will go into the debate seeking to encourage Ken Maginnis to help lead his party to the negotiating table on September 15th.
"We want a positive engagement on TV. We can all recriminate and engage in the sort of rhetoric that has passed for politics here before but let's try something new".
UUP sources said: "Most Ulster Unionists feel that it is right to take on Sinn Fein. The experience of the last ceasefire was that Sinn Fein got coverage that was disproportionate to their mandate. Nobody knows Sinn Fein quite like the unionists."
The debate is expected to last 20 to 25 minutes. Clearly conscious of the political risk the party is taking, UUP sources said of Mr Maginnis last night: "It will only work if he does well."