Revelations over the IRA informer known as "Stakeknife" have not weakened the peace process, MPs have been told.

Paul Murphy told the Commons on Wednesday that media claims of a spy operating for British intelligence at the top of the IRA's command had not damaged the province's fragile peace process.

The Northern Ireland secretary argued that given the circumstances, it should be of no surprise that the intelligence services would have sought to gain information on a terrorist group.

"I do not believe that the peace process has been in any way affected adversely by what's occurred over the last number of weeks. Obviously we have the procedures in place to deal with these matters," Murphy told MPs.

The minister also said that the security services have to operate within guidelines governing the use of informers.

On the wider problems of the suspended assembly, Murphy reiterated that "restoration of trust" was absolutely vital if elections were to go ahead in the autumn.

"We will do whatever is best for movement so that we can restore the institutions, have the elections and move forward is really what concerns us all," he said.

"Progress depends on absolute clarity both on the future of paramilitarism and the stability of the institutions."

Further talks with the political parties would continue until an agreement could be reached as all sides could not "allow a vacuum to occur in the months ahead", he said.

Shadow Northern Ireland secretary Quentin Davies questioned what concessions the government had extracted from republicans after dismantling observation towers in South Armagh.

"I hope we got progress in the process. What those two towers were about was returning to a normal society in Northern Ireland," Murphy said.

Liberal Democrat spokesman Lembit Opik called for reassurances that those who had obstructed the Stephens inquiry into collusion with paramilitaries would be identified.