Lady Sylvia Hermon, the Ulster Unionists' sole MP, will decide this week whether to run for the party leadership.
The North Down MP said yesterday she believed her party leader David Trimble would be remembered as the "party political leader who delivered the DUP to the middle ground".
She believed the party had conducted a dreadful election campaign, and that Sinn Féin and the IRA had "shafted" Mr Trimble and the UUP.
She said, however, that "the IRA must for goodness sake go away. Get on with the decommissioning. You have done it once. They crossed the Rubicon. A few years ago that was the major decision".
In an interview on RTÉ radio's This Week, Ms Hermon, whose husband Sir John Hermon is a former RUC chief constable, said the decision on whether to run for the leadership was "a hard one to call" because of family commitments.
She has two young boys and her husband has had Alzheimer's for six years. "I also care for the party, and care desperately about the future of Northern Ireland. I will think carefully over the weekend, and decide at the beginning of the week what I'm going to do."
She said her party leader would be remembered as "a man of great personal integrity, a courageous leader. The Belfast Agreement is a very, very, very courageous move. He knew it was a gamble".
Asked how she felt about being her party's only MP, she said she was often on her own at Westminster.
She believed the party ran a "dreadful election campaign", and that the slogan "Decent People . . . vote Ulster Unionist" offended a lot of people who would normally vote Alliance or SDLP.
She said "whatever Mr Adams and Mr McGuinness have done in the past, I believe very strongly that they have to be given the opportunity for change".
She was "furious" that they "had let us down so badly" and that trust was broken down. However, she added that "no matter what they have said about the RUC and the PSNI, they do ask me how my husband is", while DUP members who "have put themselves forward as the great defenders of the RUC and have never, ever asked me".
