In trial reviews, Cameron met with members of his own constituency in Witney, and left some feeling shocked. Grandmother Doris Betsy said “he came round and I offered him a cup of tea. He immediately said that I should just use the one tea bag for both cups to save money. Well, that was very clever, but then he went round the house turning off lights and plug points, and told me off for wasting electricity.”

“He stayed for about an hour,” she continued, “and at the end of it, I was shell-shocked. He handed over this sheet of paper with recommendations on it such as ’sell those old books on Amazon’ and ‘use the shower, not the bath’, saying I could make about £23.50 of savings across the year, and he told me to get a draught excluder to save on those heating bills. Some of it was bloody obvious, frankly. Then he said he’s going to come back in a year’s time and if I haven’t done what he suggested, he’ll fine me!”

Cameron’s partner, Nick Clegg, said last night that the reviews were “going to be painful”, adding “some people might not like being told they have to save money, but if we all pull together, then we can get through this. Only yesterday, David visited a man who was using twice as much toothpaste as he could be using. That represents a saving of 70p per month, and he could save even more if he switched to supermarket-own brands instead of Colgate.”

“These are the little things that are going to make the difference, you know,” he continued. “Myself, I’ve learned how to darn socks.”

The coalition government is also holding workshops, full of handy hints on how to save money around the household. David Willets will be holding a “Knit for Britain” workshop in Hull next week, while Teresa May will be coaching the people of Peterborough on how to grow carrots. William Hague, in the meanwhile, is set to tour Britain in a vegetable-oil powered Battle Bus that turns into a walk-in “cost savings” surgery, where any spendthrift consumers can pop in for a dressing down.

“This is all absolutely necessary,” insisted Cameron, “and when I meet with the people of Great Britain, I will be checking that absolutely not one single person has left their television on stand-by overnight, and that everyone has draught excluders.”

The last-minute decision to switch to a horse race was taken by current prime minister Gordon Brown after Lib Dem leader Nick Clegg proved more popular than sliced bread in a phone vote.

However, Brown is trying to divert attention away from rivals and towards the economy. Labour minister and manifesto architect Millie Headband said: “The economy is safe in our hands. We will be forcing bookmakers to pay all of their profits from the election race to the government. This money will be ring-fenced it to buy Greece and provide free holidays there for hard-working British families.”

Rules for the three-horse race are still being finalised but only the three main parties will be allowed to enter. The winner will be determined on a first-past-the-post basis. This has disappointed Liberal Democrats, who wanted an element of proportionality in the outcome. UKIP are reported to be furious at the decision to make it a three-horse race, claiming that Nigel Farage could have easily taken part, as he is half-horse himself on his mother’s side.

Lib Dem spokesman Lemsip Cableknit said: “We wanted the number of bets placed on each horse to be taken into account. As it stands, one horse can win despite gaining only a small proportion of the betting. That is patently unfair.”

SNP leader Alice Salmontickler is furious at being left out of the race: “Limiting the race to only three horses is an outrageous injustice typical of this London-centric policital system. We have perfectly good horses in Scotland. They keep leaving me out of everything and it just makes me want to cry.”

The Green Party has expressed disappointment at being left out of the running but has welcomed the radical move. Its leader, Carrie Online-Ludicrous, said: “We applaud putting sustainable transportation like horse riding centre stage. This race will have a lower carbon footprint than millions of voters travelling to polling booths, too.”

Conservatives have criticised the move to a three-horse race for not going far enough. “This is typical of the half-baked, opportunistic proposals we have come to expect from this government,” said Alexander St John  Spigginbottom, an aide to David Cameron. “Under a Conservative government, I can guarantee that future elections will be decided not by three horses, but lots of horses and lots of hounds pursuing whoever is the Lib Dem leader at the time.”

“I have to admit”, he admitted, “I was a little bit surprised that nobody said anything. They didn’t even seem uncomfortable about having me sit naked among them. At one point, I got really close to this snotty Tory fella and he didn’t even stir. Even when I got up to ask questions, it was as if I wasn’t there.”

Fellow MPs, when told that Nick Clegg was stark nackers naked during PMQs said that they “were astonished”. MP for Shytte South Brianna Zoology-Degree said that it was “revolting”, and asked for television footage so that she could have a proper look.

Lib Dem MP for Cackwater North, Alan Bypass-Smith, said that he fully supported Nick Clegg’s nakedness, and encouraged other Liberal Democrat MPs to follow suit by ditching their two-party system suits and going nuddy in the House of Commons.

“I didn’t notice it at all until Nick came up to me in the tea room afterwards and asked me what I thought of his performance. I said the usual platitudes, you know – great questions, well done, back slapping, all that – and then he asked me what I thought of his cock. I was taken aback. So when I got home, I looked on YouTube, and there he was – starkers! He was probably starkers when he was talking to me afterwards, too. I just don’t remember.”

Clegg himself said that he would continue to try and get someone’s attention, and is rumoured to be thinking of emulating the late Lib Dem MP Martin McWretched whose virtuoso 30-minute display of auto-erotic asphyxiation, which went horribly wrong and almost resulted in his death during a debate on the NHS was completely and utterly ignored by the entire house, and was only discovered by cleaners a week later.

“I might give that a go,” mused Clegg. “And next week, I think I’ll go wearing the wife’s clothes. Not that I’m trying to get attention, they’re just comfortable and I know nobody will see me.”