Lord Alderdice was appointed as Presiding Officer of the Assembly by Northern Ireland Secretary Mo Mowlam on Monday, only hours after he resigned as leader of the Alliance Party.

His surprise resignation from the head of the party that has pioneered cross-party politics in the province, became effective from Tuesday morning.

Lord Alderdice on BBC Radio 4's Today programme

Speaking on Radio 4's Today programme he tried to diffuse tension in the build up to the Drumcree march on July 5.

"The cause of peace will not be served and no-one's interests will be served by the law being broken."

He went on: "I think everybody wants to see some calm. David Trimble has issued a letter in his own way appealing for calm in what is, after all, his constituency.

"We hope that that's what will happen. It's extremely important that everyone avoids putting the RUC in an invidious position of being attacked by both sides. It may be that it's possible for something to be done indirectly."

Orangemen marching at Drumcree last year

Lord Alderdice reaffirmed the Alliance party's position as "non-aligned" in the sectarian divide.

"We are there. We're not unionist or nationalist," he said.

He also dismissed reports that he had stepped down as party leader in order to become new assembly speaker.

"What I have asked to do is to act as interim speaker until someone else is appointed," he said.