A potential crisis is looming at Stormont with doubts emerging over Sinn Fein supporting Peter Robinson's nomination as First Minister to replace his former party leader, Ian Paisley.

Despite Peter Robinson's insistence at the weekend that any notion that Sinn Fein is prepared to derail his elevation to the top position was "ludicrous", the Sinn Fein leadership is expected to meet Prime Minister Gordon Brown in London this morning.

Sinn Fein is thought to be unhappy at what they perceive to be the DUP's continued veto of devolving policing and justice, and other issues so are using the threat of a crisis - which could result in an Assembly election being held to break the deadlock - to present a list of demands in No 10 today.

Originally, it was expected to be a mere formality on Thursday after Ian Paisley stepped down to be replaced by Peter Robinson once Sinn Fein nominated Martin McGuinness as Deputy First Minister, given that, technically, McGuinness will also be out of as job following Paisley's departure.

If Mr McGuinness is not nominated, the two parties have one week to resolve the issue before the Secretary of State Shaun Woodward steps in and could call an election to break the deadlock.

The potential crisis is serious enough to have got the attention of both London and Dublin with telephone diplomacy involving the two governments.

Indicating the content of SF's list of items for Gordon Brown, Sinn Fein President Gerry Adams said his party was focused on talks to resolve outstanding issues such as the devolution of policing and justice and an Irish language act.

But Mr Robinson has dismissed the threat and said: "It's inevitable that if they do not nominate there will be an election and it will be like Groundhog Day all over again."

See: SF Attempt To Stymie Robinson's First Minister Job 'Ludicrous'

See: Incoming First Minister Faces Range Of Issues

(BMcC)