AMID all the uncertainties of politics, one thing is sure – there will be a general election in less than six months.
There is still speculation over what date Gordon Brown will choose – an election on 25 March would allow the budget to be postponed until afterwards, though 6 May still seems the most likely, coinciding with local elections south of the Border.
But the Prime Minister must call an election sometime between now and the last possible option for polling day, 3 June.
When it comes, there is a chance – more so than at any time in living memory – that all five Edinburgh seats could end up with a new MP.
Two will certainly have a different representative at Westminster after the election because current MPs John Barrett and Gavin Strang are standing down.
But the other three incumbents – Nigel Griffiths, Alistair Darling and Mark Lazarowicz – are being heavily targeted by their opponents.
Mr Griffiths, MP for Edinburgh South since 1987, has the smallest majority in the city. Just 405 votes separated him from the Liberal Democrats' Marilyne MacLaren last time.
The Lib Dems – who already hold the seat at Holyrood – have made the seat their top target with candidate Fred Mackintosh and believe they can take it.
The Tories, who held the seat up until Mr Griffiths won in 1987, are also targeting it, despite finishing a clear third at the last election. And the bookies have made their candidate, Neil Hudson, the favourite to win, with the Lib Dems second and Labour third.
However, one Labour insider is convinced Mr Griffiths can hold the seat again. He says most voters will not remember the MP's front-page appearance in the News of the World over an alleged sex romp with a mystery woman in his Commons office.
He claims the Lib Dems are at a greater disadvantage since the last election because they now have to defend their record in power on the city council, and he says the Tories and Lib Dems will cancel each other out, leaving Mr Griffiths the winner.
The Lib Dems insist people are aware of the closeness of the result last time and therefore realise it is they who are the main challengers. "People feel let down by Labour and they like what Vince Cable says on the economy," says one leading Lib Dem in the constituency.
The Tories say Edinburgh South voters respond well to David Cameron and claim they have a better chance of winning the seat than for some time, but admit privately it is difficult coming from third place.
Edinburgh East, where Labour's Gavin Strang is standing down after 40 years as the MP, will be a closely fought battle between two former city councillors – Sheila Gilmore for Labour and George Kerevan for the SNP.
The Nationalists' Kenny MacAskill caused an upset at the Holyrood elections when he won the equivalent seat from Labour, so the SNP goes into the Westminster contest with high hopes.
However, the boundaries are different from the Holyrood ones, removing Musselburgh and adding Liberton, Gilmerton and Moredun. Labour believes it can hold the seat despite losing the advantage of the personal vote Dr Strang built up over the years.
Edinburgh West is the second safest Liberal Democrat seat in the UK, so there is little chance of it being lost. But voters there will still end up with a new MP on election night because John Barrett, who was first elected in 2001, is standing down. His place will be taken by former policeman Mike Crockart.
The Tories seem to be putting their biggest effort into trying to oust Chancellor Alistair Darling in Edinburgh South-west. The Conservative campaign for candidate Jason Rust has already seen a host of shadow cabinet ministers come north to brave such unlikely Tory territory as the Westside Plaza shopping centre in Wester Hailes.
Voters have even been receiving Christmas cards, calendars and fridge magnets in a bid to win them over.
The Tories say they are getting a good response and are reaching into areas which are not traditionally their territory.
Mr Darling would be a big prize if they were able to defeat him, but Labour is only too conscious of that and will be throwing all it can at the campaign to keep him in place.
He had a majority last time of 7,242 so it is not really a marginal seat. Labour's main task will be to make sure its supporters turn out to vote.
Labour's Mark Lazarowicz in Edinburgh North & Leith is being targeted by the Lib Dems, who cut his majority to 2,153 last time.
They believe their candidate Kevin Lang can win because of the mood for change and their position as the main challengers, together with the continuing change in the population of the constituency. One source said: "There has been quite a lot of new-build at the waterfront since 2005 and the people moving in are the young professional couples who tend to vote Lib Dem."
Labour insiders, however, say Mr Lazarowicz is popular in the area and they believe the Lib Dems' record on the council will put them on the back foot.
Gordon Brown will probably not name the date until towards the end of February at the earliest – but in reality the election campaign is already well under way.
2005 GENERAL ELECTION RESULTS:
Gavin Strang Lab 15,899
Gordon Mackenzie Lib Dem 9,697
Stefan Tymkewycz SNP 6,760
Mev Brown Con 4,093
Lab majority 6,202
EDINBURGH NORTH & LEITH
Mark Lazarowicz Lab 14,597
Mike Crockart Lib Dem 12,444
Iain Whyte Con 7,969
David Hutchison SNP 4,344
Lab majority 2,153
Nigel Griffiths Lab 14,188
Marilyne MacLaren Lib Dem 13,783
Gavin Brown Con 10,291
Graham Sutherland SNP 2,635
Lab majority 405
EDINBURGH SOUTH WEST
Alistair Darling Lab 17,476
Gordon Buchan Con 10,234
Simon Clark Lib Dem 9,252
Nicholas Elliott-Cannon SNP 4,654
Lab majority 7,242
John Barrett Lib Dem 22,417
David Brogan Con 8,817
Navraj Ghaleigh Lab 8,433
Sheena Cleland SNP 4,124
Lib Dem majority 13,600