'Where is Peter Robinson? I want to speak to Peter Robinson – now!" a woman in a two-up, two-down house off east Belfast's Newtownards Road yells at David Vance, eying his red-white-and-blue rosette.

The Traditional Unionist Voice candidate explains that he has nothing to do with the DUP. "I'm the man who wants to get rid of the Robinsons," Vance explains. And suddenly the woman is all smiles and handshakes and promises her vote.

The anger towards Peter Robinson in working-class loyalist streets, among people who supported him for years, is immense. He was the youngest MP in the House of Commons when East Belfast first elected him 31 years ago.

"He's been in power longer than Robert Mugabe. He's out of touch and out of time," declares Vance. "Just look at the deprivation in these streets and think of the luxurious lifestyle of Peter and Iris Robinson. They earn £571,000 [€656,000] a year and people here are struggling to make ends meet." A woman in the Braniel produces a DUP leaflet torn in two: "I ripped it up in front of the DUP canvassers. I voted for the party all my life but no more. They've betrayed us."

This time, when people talk of "betrayal" they don't mean the DUP being in government with Sinn Féin. They mean the Robinsons' financial affairs. A deal in which the couple bought and later sold a valuable piece of land for £5, which then enabled them to sell part of their back garden for nearly £460,000, is brought up time and time again.

"I can't wait for Peter Robinson to call asking for our vote. We'll tell him where to go," a man in his 30s says. But such an opportunity may not arise. The Sunday Tribune had no problem joining DUP candidates in other constituencies out canvassing. But the DUP leader himself proved elusive. After unsuccessful telephone attempts, we were told we had to email our request to join Robinson – unheard of in the small world of Northern politics. The email request went unanswered.

"'Where's Peter?' that's what people are asking on the streets," says Vance. "He's not usually so shy." Robinson has a 6,000-vote majority. "It's the TUV's first Westminster election so it's a big ask for me to take the seat but I still think I can. We're punchy and in-yer-face about the DUP with voters. Being nice won't get rid of Robbo. The TUV is a new party, untouched by sleaze and scandal."

Judging by the last Westminster poll, the Ulster Unionists – who have an electoral pact with the Tories for this election – are the clear favourites to capitalise on Robinson's unpopularity. In 2005, UUP leader Reg Empey was runner-up in the constituency. This time, however, he's standing in South Antrim and East Belfast is being contested by former Irish rugby international Trevor Ringland.

'Developers Unionist Party'

He is a non-sectarian unionist known for his cross-community work and has a less aggressive approach to canvassing than Vance. "I don't mention the Robinsons and when voters bring it up I don't comment. My wife has told me to run a positive campaign – not to be nasty on the doorsteps – and she's the boss!" he says.

"Keep Northern Ireland moving forward"; "Let's bring in normal politics"; and "It's time to get things working here," he tells voters in Ballybeen.

UUP peer John Laird, who arrives in his navy Merc to join the canvass, urges a less genteel approach: "Sometimes, I worry that Trevor is too nice. We need to be saying 'get rid of the Robinsons'. That's the mood on the streets. People have signs up saying 'DUP don't call here'. They've nicknamed it the 'Developers Unionist Party'."

Ringland jokes: "I need to keep John on a leash." But Lord Laird is unperturbed. "I don't even have a vote in the election," he says. "Peers and lunatics are barred from voting – you can make up your mind which category I'm in."

Alliance candidate and Belfast lord mayor Naomi Long believes that although her party was significantly behind both the DUP and the UUP in the last Westminster election, she can take the seat.

Passionate and articulate, she has a high public profile and likes to tackle issues head-on. "There's real anger towards Peter Robinson on the doorsteps. There was some sympathy for him after the revelations about Iris but the land deal changed that. And people don't like his 'angry man' TV performances."

'Not frightened of Peter Robinson'

Long says the decision by UUP leader Reg Empey to run in South Antrim, and not his own constituency of East Belfast, smacks of cowardice: "He put up the white flag and effectively said he couldn't win in East Belfast. In me, people have someone not frightened to take on Peter Robinson and the DUP in this constituency."

East Belfast remains impossible to call. The fact that the opposition to Robinson is split three ways means he might pull through. The TUV's robust approach will go down best in working-class areas. Ringland will be stronger among the middle-class.

The bookies believe Robinson will retain the seat but if Vance takes enough votes from the DUP, Ringland could snatch it. However, David Cameron's suggestion that he would target the North for spending cuts could seriously damage Ulster Unionist and Conservative candidates.

The DUP seemed set for a big fall in Strangford, the constituency represented by Iris Robinson. It's not just that the woman who preached against premarital sex and homosexuality had a toyboye lover, it's that she was able to so easily secure £50,000 from a property developer friend to set Kirk McCambley up in business.

But if there's a crisis in the local DUP, it's not at all obvious in the party's campaign headquarters in Newtownards. Candidate Jim Shannon couldn't be more unlike Mrs Robinson.

He's too much a party loyalist to say so but they never got on. In normal circumstances, Shannon wouldn't have been the party hierarchy's choice for the nomination. But after all the scandal, a man with 25 years' experience as a councillor and who is known for his first-class constituency work is what's required.

There's nothing pretentious about Shannon. He's old-style DUP with very traditional interests. He's a member of all three loyal orders – the Orange Order, Apprentice Boys, and Royal Black Institution. Photos adorning the wall show him enjoying his favourite pastime – shooting.

"Rambo Jim", as a local newspaper has nicknamed him, can be seen aiming at pigeons in Argentina, or with Ian and Eileen Paisley.

There are many pictures of the Paisleys in the office but, notably, none of the Robinsons. Another passion is the Northern Ireland football team, as pictures of Shannon with David Healy – "before he was famous" – and a 1982 World Cup tea towel show.

The office is littered with thank-you cards and boxes of chocolates and biscuits from grateful constituents. "I was only a size 12 until I came to work here," says Naomi, one of Shannon's dedicated workers.

Admirers among the ladies

On the streets, Shannon is surrounded by well-wishers – the butcher, the postman, and the Chinese fast-food delivery guy. But, like Mrs Robinson, Shannon does have his admirers. Several elderly Strangford ladies, he confesses, have started buying him ties.

Shannon's main rival for the seat is Ulster Unionist and Conservative candidate, former UTV news presenter Mike Nesbitt. "People need somebody new," he says, "and I'm the man for the job".

He jokes about how he's had a few mishaps since entering the political arena – he fell off a ladder when putting up posters on the first day of the campaign – but, he says, he's thoroughly enjoying it.

Nesbitt gave up a £65,000 job as one of the north's four victims' commissioners to contest the seat. "I have no safety net, no personal plan B. On 7 May, I could be selling the Big Issue," he jokes. "It's a leap in the dark but it's worth it. Strangford needs a strong voice in parliament with a positive message.

"During the Troubles, our politicians were naturally always pointing out what was wrong. But times have changed and someone like me can promote Northern Ireland and show what we have to offer."

The DUP has accused Nesbitt of snobbery and arrogance, claiming he said Shannon wasn't fit for Westminster and should stick to dealing with "pot-holes in Portaferry".

Nesbitt says his words have been misinterpreted: "What I said was that Jim is doing very good work on the ground as a councillor and Assembly member and perhaps he should stay where he's most needed and let a fresh face go to Westminster."

He says the DUP's attitude to his candidacy sums up the worst of unionist politics: "It's so negative. It's 'attack, attack, attack' and the guy from the TV is an easy target. I'm fed up with it and so are a lot of people in Northern Ireland."

Ask Nesbitt how he's doing and he laughs – "as far as I know I couldn't tell you". He's not one for "number-crunching" either: "Look, it could all depend on the weather. Jim Shannon's voters will turn out come what may. A wet day could cost me."