How Rory Bremner had Oxford Lib Dem supporters squirming in their seats a few weeks back. “I met Nick Clegg the other day,” he told a packed New Theatre audience at the big comedy fundraising night for Helen House. “He said to me, ‘Rory, can you do me?’. I said, ‘No. Can you?’.”

A most definite case of the bland leading the bland, the impersonator added as the place erupted in laughter. Well, it looks like Mr Clegg may have forced a change in Rory’s stand-up routine, as well as the shape of the political landscape.

Rory might still not be able to do Nick, but we all now know that Nick can certainly do the polished political outsider to perfection, requiring a mere 90 minutes to win over half the electorate.

Steve Goddard, who is hoping to win Oxford East for the Liberal Democrats from Labour’s Andrew Smith, actually missed the beginning of the first leaders’ debate. But he hardly needed to watch it on his video to grasp the impact that his leader had made.

“I went out knocking on doors the following day in Littlemore,” he recalls. “The first four houses that I visited on Friday morning not only said they would vote for me, they took posters to display in their windows as well.”

Of course, Mr Goddard could, in any event, have expected a warm welcome on the doorsteps of the city this week. He only failed to win the seat in the last General Election by 963 votes and Oxford East is now judged by the Lib Dem to be their fourth most winnable seat.

Never mind hung parliaments and Lib Dems in government, winning Oxford East now almost appears a minimum requirement to meet current sky high Lib Dem expectations.

But Oxford East is not your average constituency. Few seats outside London can come close to matching it in terms of sheer diversity, taking in as it does Iffley, Headington, Cowley, Littlemore, Barton, Blackbird Leys and now a large slice of the city centre.

The Boundary Commission review means that in addition to Oxford Brookes University, it contains the majority of Oxford colleges too, ensuring that it has one of the country’s biggest student populations.

As an island of red in a region predominantly blue, the seat has always been symbolically important to New Labour, as the former home of British Leyland and Rover that has successfully transformed itself into a thriving high-tech economy, with world-class research and modern business parks.

Gordon Brown, both as Chancellor of the Exchequer and Prime Minister, has been a regular visitor to the BMW plant — and it was no surprise when Mr Brown turned up at the factory this week to remind everyone of the Mini success story.

For the Liberal Democrats, who have managed to turn neighbouring Oxford West and Abingdon into something approaching a safe seat, Oxford East holds out the tantalising prospect of turning the whole city of Oxford yellow on May 6.

As for the Conservatives, well, they can point to the fact that Steve Norris won the seat for the Tories during the Thatcher years. Their candidate Ed Argar, who between 2001 and 2005 was political adviser and speechwriter to Michael Ancram, the then deputy leader of the opposition and shadow foreign secretary, predicts a tight race between all the parties.

“It is easy to point to 2005 and draw conclusions from out-dated statistics. But a lot has changed in the last five years,” he says.

As for the Greens, they will be encouraged by the number of councillors that are regularly returned in local elections by voters in East Oxford.

But for all the national opinion polls putting the Lib Dems well ahead of Labour, Mr Goddard certainly has no expectation of being swept to Westminster on the back of his leader’s sudden popularity.

“I think it is going to be a damn close thing here. I think the leaders’ debate has been important. Whether it is decisive, I’m not so sure.”

It was certainly mentioned by a number of voters he met in Boswell Road on Monday, when I joined Mr Goddard during an afternoon’s canvassing, to measure the level of Cleggmania in Cowley.

One man answering the door wearing nothing but a towel felt impressed enough to stand chatting for five minutes, while a civil servant who described herself as being “Old Labour” said that while she had thought well of Clegg’s performance, she was altogether more concerned about the threat to both her job and her pension.

Another bare-chested resident in his 20s declared he would not be voting at all. The leaflet Mr Goddard handed to him had no smiling Clegg on the cover, and had no reference to the national debt, taxing bankers or reviewing Trident missiles.

The second sentence referred to “the fight to stop Labour from closing our local public toilets”.

The next paragraph dealt with the campaign for “mandatory licensing schemes to tackle dodgy landlords that have been allowed to exploit students and young people”.

The student vote adds to the unpredictability of the Oxford East result.

In 2005, the issue of top- up fees was judged to have been almost as costly to the Labour cause in the constituency as the Iraq War. It was significant that a planned visit by Nick Clegg to the constituency that had been earmarked for Tuesday, was to have centred on Oxford Brookes University. The visit is now expected to take place in the last week of the campaign.

Mr Smith’s leader arrived to offer his support on Wednesday, bringing along not only his wife, Sarah, but two of the biggest guns in his Cabinet — Lord Mandelson and Ed Miliband. Together they toured the factory, held to be an impressive example of how a committed workforce could pull together through a recession, with the Mini plant chosen as a fitting location for the Prime Minister to announce plans to invest £1bn to secure the future of British manufacturing.

Having previously worked as Mr Brown’s number two in the Treasury, Mr Smith is viewed as a close and trusted friend of the Prime Minister, something of a double-edged sword, you might think, looking at Mr Brown’s personal poll ratings.

But Mr Smith can expect to reap the rewards of having left Government “to spend more time in his constituency”, even if cynical commentators claimed he jumped before he was pushed by Tony Blair.

The long-serving Labour MP points to the fact that he has built up relationships with constituents over years.

“I have not found any widespread sense of disillusionment with politics. What I’m finding is thoughtful people weighing things up. The fact I was one of a minority of MPs who has not had to repay money has meant MPs’ expenses is less of an issue here than in other constituencies.”

Less surprisingly, like his Tory opponent, he says he has not detected any evidence of a Clegg bounce locally “One thing that is going to happen is that Lib Dem policies will come under closer scrutiny.

“You have to remember if opinion moves one way suddenly, it can move the opposite way as well. The one important over-riding issue for people is securing economic recovery and not a double dip into recession.

“But every kind of issue comes up in this constituency. Nothing would surprise me. It is worth pointing out that in the local election results, Labour bucked the national trend. I think there is something special about Oxford.”

He also points to his record as a backbencher, which has seen him vote against unpopular policies backed by the Brown leadership on issues as diverse as the Gurkhas, Trident and power station pollution levels.

His support for the Iraq War, however, is something he has been forced to defend once more.

“I voted on the best information I had available and in good faith. I regret that information turned out to be incorrect. If we knew then what we know now, the course of history would be very different,” he said at the hustings last week.

UKIP candidate Julia Gasper said her party was the only one that would remove a PM’s power to go to war without a Parliamentary vote.

At the same packed meeting, a passionate appeal to shun tactical voting was made by Sushila Dhall, the local councillor who is standing for the Greens. “Don’t be persuaded that because it’s a marginal seat you should vote negatively to keep someone out. Vote for what you believe in.”

Affordable housing is something both the Greens and Tories have identified as a major local issue.

Tory candidate Mr Argar said: “One of the big issues coming up on the doorstep is how to balance the need for affordable and decent-sized family housing with the need to protect our green spaces.”

In part, the problem can be addressed by using boarded-up council properties, he says, but more fundamental is the need to devolve key planning decisions from central and regional government back to local communities.

The high number of students has greatly increased the urgency of the affordable housing issue, argues Sietske Boeles, a well-known local campaigner and a founder of the Friends of Warneford Meadow.

“When I went to the hustings, I was struck about how little difference there is between the three main parites. They all want a fairer society and to protect the NHS. But it was all a little bland.

“They are all being so cautious, with no personal attacks. I think everyone is aware that Andrew Smith has been a good constituency MP.

“But there are many local issues that need to be addressed, like the huge levels of inequality in this constituency in terms of health and wealth. It is shocking that the life expectancy of someone living in Blackbird Leys is 13 years shorter than someone in North Oxford.

“Then there is the issue of crime. There is a huge level of anti-social behaviour here. It was ironic that on Sunday there was a stabbing in Manzil Way, just across the road from where the hustings were being held.”