BRITISH Prime Minister Gordon Brown held crisis talks with both Sinn Fein and the Democratic Unionist Party (DUP) this week to avert the potential collapse of the power-sharing Executive at Stormont.On Tuesday Sinn Fein leaders Gerry Adams and Martin McGuinness flew to London for talks with Brown over fears that the power-sharing Executive could collapse within days.On Thursday new DUP leader Peter Robinson was expected to be nominated by the Assembly to take over the role of Stormont's first minister from outgoing leader Ian Paisley.Under Stormont rules Robinson can only be appointed as first minister if Martin McGuinness is nominated alongside him as deputy first minister.However there were real concerns that Republicans could refuse to put McGuinness' name forward as deputy first minister amidaccusations that Unionists have deliberately blocked the introduction of legislation, including the transfer of policing and justice powers and an Irish language act.If McGuinness' name is not put forward by Sinn Fein, Secretary of State Shaun Woodward could be forced to dissolve the Assembly and call an election within days.While Sinn Fein has refused to comment over the potential collapse of the power-sharing institutions, Republican sources insist that Unionists had agreed to the transfer of policing and justice powers as far back as 2006. The deadline for the transfer of those powers to the Stormont Assembly passed without movement last month.However, Unionists blocked the move, claiming it was too early for the transfer and that they needed more assurances from Republicans, including the disbandment of the IRA's Army Council. Robinson, who also held crisis talks with Brown on Tuesday, insisted that his party would not be pushed into making concessions to Republicans over policing and justice.He said if Sinn Fein refused to nominate McGuinness fresh elections could be called within a week."I believe we are in a strong position, there is nothing out there that I fear," he said. "Nobody has anything better to offer."While Adams refused to make any comment after his meeting with Brown on Tuesday, he had earlier said, "Eighteen months ago the two governments and all the political parties including the DUP accepted that the St. Andrews Agreement was the basis upon which the political institutions were put back in place."The St. Andrews Agreement set out a number of commitments andobligations which have to be honored. These include the transfer of powers on policing and justice which was to be concluded by May and an Irish Language Act. These are key issues of democratic accountability and equality. "Progress has been made over the course of the past 12 months in bedding down the political institutions. It is Sinn Fein's intention that this work is built upon in the time ahead including progress on the outstanding issues."We continue to be involved in detailed discussions aimed at achieving this."Paisley, who stepped down as DUP leader last week, praised Sinn Fein for its role in delivering peace.In a speech before hundreds of supporters at a rally to mark his retirement, Paisley said, "Those who killed gallant members of the RUC now publicly support the police by a signed pledge, they cooperate with them and supply the police with valuable information which I hope will see the ending of the IRA Army Council."There has been an amazing turnaround, and please God wewill see it come to full fruition."In other political news, on Tuesday Belfast City Council elected a new lord mayor from Sinn Fein, marking only the second time that the post has been filled by a party member.Tom Hartley defeated Diane Dodds of the DUP by a vote count of 25-23.