It was all so different for the DUP in the Westminster election five years ago. Its 'Battlebus' invaded towns and villages across the North, and there wasn't a chink in the party's armour.

It emerged with nine seats and 34% of the vote. After 6 May, it certainly won't be on anything like that vote and its number of MPs could well be down. Private DUP polls show it only slightly vulnerable in one seat – South Antrim – where Ulster Unionist Party (UUP) leader, Reg Empey, is taking on the Rev Willie McCrea. But that looks very optimistic.

Scandals over expenses, property deals, Iris Robinson's affair with a toyboy and her husband's recent bad-tempered TV performance have all taken their toll. The winners seem set to be Jim Allister's Traditional Unionist Voice (TUV) and Reg Empey's UUP which has an alliance with the Tories for the election.

As well as North Antrim, which Allister is contesting, the TUV should poll well in East Belfast where businessman David Vance is running against Peter Robinson and in East Derry where former MP Willie Ross, at the grand old age of 74, is standing against the DUP's Gregory Campbell, who took the seat off him in 2001.

The Ulster Unionists' best chance of a seat is South Antrim. The party also hopes former UTV presenter and victims commissioner Mike Nesbitt can take Iris Robinson's old seat of Strangford. Nesbitt's popularity will help, but DUP candidate Jim Shannon is a first-class constituency worker.

A massive compensation package from Libya for the victims of IRA violence could well be announced just before the election in a deliberate attempt to bolster the ailing DUP. In East Belfast, lord mayor Naomi Long should poll strongly for Alliance.

Only one of Sinn Féin's five seats is vulnerable. Its hugely likeable agriculture minister Michelle Gildernew for the first time faces a single unionist candidate, Rodney Connor in Fermanagh and South Tyrone, the constituency once so famously won by Bobby Sands. She'll need 90% of the nationalist vote if she's to retain the seat. The SDLP is standing high-profile ex-UTV presenter Fearghal McKinney.

Despite recent revelations over his alleged role in the murder and secret burial of Jean McConville, and his lying about his brother Liam, Sinn Féin president Gerry Adams isn't in danger of losing his west Belfast seat where he won 71% of the vote last time with the SDLP's Alex Attwood on 15%.

Grassroots disillusionment with Sinn Féin means the party will lose traditional republican support but it will be helped by the fact that the election is little more than a sectarian headcount in many constituencies and that the SDLP still doesn't look like a real alternative.

It's the SDLP's first election under new leader Margaret Ritchie. It's vital the party holds onto its 17.5% of the vote and its three seats, South Belfast, Foyle, and South Down, where Ritchie herself is running against Sinn Féin's Caitriona Ruane.