Election 2015: The place where one street could decide the MP
As the main political parties launch their manifestos, the battle for marginal seats - constituencies which only require a slight swing to change hands at elections - has arguably never been more important. But what's it like to live in an ultra-marginal seat, and how critical are they?
Chat to voters in the constituency of Camborne and Redruth, a four-way marginal seat almost at the very tip of south-west Cornwall, and nobody seems to know what is going to happen on 7 May.
"I have no idea. A lot of people are looking for UKIP to win, but I hope that isn't the situation. I don't remember an election that seems this unsure," says 25-year-old Hannah Sleeman, a head chef at the town's Tesco.
"It will be a tight call, I haven't got a clue," agrees 75-year-old David Marshall. "If I had to hazard a guess, I'd say the Tories will win."
Ken Anstis, 83, thinks it could go the other way. He thinks Labour might get in locally and form a minority government.
The constituency - which was first created in 2010 after boundary changes - was won by the Conservatives by just 66 votes last year.
That's roughly the equivalent of 32 houses - or just one street.
What is a marginal seat?
- There is no fixed definition of a marginal, but if we choose to define them for the 2015 general election as seats with majorities of 10% or less that require a swing of 5% for the incumbent party to lose, then there are currently 194
- 82 are Conservative, 79 Labour, 27 Lib Dem, three SNP, two Plaid Cymru and one Green
- Marginal seats are not evenly spread: within England, 15% of seats in the South East have majorities of 10% or less, compared with 51% in the South West. In Scotland, 19% of seats fall into this category, compared with 45% in Wales
- There are five marginal seats in Northern Ireland (28%) - which is home to most marginal seat in the UK. Fermanagh & South Tyrone was decided by just four votes in 2010.
Back then, the tightly contested seat was a close-run thing between the Tories (who won 37.6% of the votes) and the Liberal Democrats (who won 37.4% of the votes).
But the UK's political landscape has changed significantly since 2010. There has been a collapse in support for the Lib Dems, while the rise of smaller parties such as UKIP, the SNP and, to a lesser extent, the Greens, has created a more fragmented political scene.
Traditional mainstream parties have also taken a hit. Some 12% of voters did not support the Conservative/Labour/Lib Dem parties in 2010 - compared with 26% in December 2014, according to 18 opinion polls.
Recent polling in the constituency has been mixed, creating a confusing picture. The latest Ashcroft poll put the Tories ahead on 37%, Labour on 24%, UKIP on 14% and the Lib Dems on 13%. The Greens were on 8% and "others" on 3%.
In Camborne and Redruth, party activists are feeling the pressure.
Adam Cricket, a local councillor for the Labour party in Camborne, says the party has been knocking on doors "two or three times" every day.
He says the seat is "very, very tight" but insists it can only go one of two ways - Labour or Conservative.
Conservative party activist Will Haslam agrees. "A lot of people may have voted UKIP [in the European elections] in May, but when it comes to the general elections, people will take the vote more seriously... the Conservatives will get more votes," he says.
But UKIP activist James Tucker says the electorate he speaks to "want UKIP".
"They are fed up of the people in power, and UKIP is a breath of fresh air," he says.
The idea of UKIP getting into power in Camborne and Redruth isn't far-fetched.
A poll of 500 voters by Survation and Exeter University in November 2014 put UKIP slightly ahead in the constituency, on 33%, with the Conservatives on 30%, Labour 22%, and the Lib Dems on 6%.
But the Liberal Democrats are fighting hard for every vote too, arguing opinion polls improve when the name of their candidate, who won the former constituency of Falmouth and Camborne from Labour in 2005, is put to voters.
"The only polling that matters to me is the poll on election day," says Lib Dem activist Matthew McCarthy.
It is no surprise parties are taking marginal seats like Camborne and Redruth seriously.
Marginal seats - of which there is no fixed definition, but which can be seen as seats with majorities of 10% or less that require a swing of 5% for the incumbent party to lose - matter.
Although 650 seats are being contested in the election, fewer than one in 10 seats changed hands from one party to another in 12 of the 17 elections since 1950.
Even in the massive Labour landslide of 1997, some 70% of seats stayed with the parties defending them.
Polling expert Prof John Curtice says marginal seats will be more fiercely fought over than ever this year.
"The last time an election was this close and unpredictable was more than 40 years ago, if opinion polls are to be believed," he says.
"And the idea the election is simply about two or three parties is no longer the case. In terms of votes - there are six parties on this side of Irish Sea that are significant players," he says.
Prof Curtice believes whoever becomes the largest party in government "probably depends on the outcomes of two battles - between Labour and the SNP on the left, and the Conservatives and UKIP on the right".
The tightly fought contest will also probably boost turnout in marginal constituencies, he predicts.
Marginal seats are not evenly spread around the UK. The South West has the most seats with majorities of 10% or less in the UK - a total of 51%. In Scotland, 19% of seats fall into this category, compared with 45% in Wales and 15% in the South East.
There are also five marginal seats (28%) in Northern Ireland - which is home to most marginal seat in the UK. Fermanagh & South Tyrone was decided by just four votes in 2010.
Which means the South West may have a big say in the outcome of election.
For the voters in Camborne and Redruth, the thought of their seat as an ultra-marginal is met with a mixed reaction.
"There are lots of strong candidates, it's going to be a close call. I will definitely be voting," says 38-year-old Stuart Pitts.
But 56-year-old Pauline Hichens says she's "very disillusioned".
"For the first time in my life, I'm wondering whether I will vote as don't trust any of them," she says.
The candidates for the constituency are:
- George Eustice (Conservative)
- Michael Foster (Labour)
- Geoff Garbett (Green)
- Julia Goldsworthy (Liberal Democrat)
- Loveday Jenkin (Mebyon Kernow)
- Bob Smith (UK Independence Party)