Massive pressure is mounting on Alasdair McDonnell to step down as SDLP leader after one of the party's most senior members called for change at the top.
Mark Durkan, the MP for Foyle and a former SDLP leader, said Mr McDonnell could not lead the party into next year's Assembly elections from Westminster.
Mr McDonnell has faced major criticism for holding onto his South Belfast Assembly seat while also being an MP for the area.
He held the seat in the general election at the start of the month, but on a much-reduced majority. The overall SDLP vote was also down by 2.6%.
Even though Mr McDonnell must quit one of his two elected positions next year when double-jobbing is outlawed, he has made it clear he wants to cling on to his Assembly seat for as long as possible.
Internal tensions are high, and many in the party feel Mr McDonnell's position has already cost it votes.
Last night Mr Durkan told the BBC's The View that Mr McDonnell "should make a clear decision in relation to the leadership".
"I don't think the party can be led into an Assembly election from Westminster," he said.
"If Alasdair thinks that just resigning from the Assembly deals with the questions, well it won't, because these questions will all surface again once he resigns from the Assembly.
"As we move towards an Assembly election, the questions won't go away and therefore I think if we're going to be in a better position to fight the election, then the leadership needs to change."
Mr McDonnell first won the South Belfast Westminster seat in 2005. In 2010, he received 14,026 votes, a 41.0% share. His majority was 5,926.
But on May 7, his majority was reduced to just 906 over the DUP - who would probably have taken the seat had Ukip candidate Bob Stoker not stood.
Mr McDonnell's 9,560 votes represented 24.5% of the vote - a massive drop of 16.5%.
He also had the dubious distinction of having the lowest ever share of the vote by a British MP.
But yesterday he continued to defy calls from party stalwarts such as Seamus Mallon and Brid Rodgers, who also called for him to step aside.
He told the BBC: "I'm not going to run away from a task half done."
And he also told UTV: "I was re-elected leader of the SDLP last November, I was elected some three-and-a-half years ago on a very clear mandate to renew, rebuild and reform this party.
"That process is well under way."