Will the G20 bounce hasten the election?

British Prime Minister Gordon Brown is notoriously sensitive about the timing of the next Westminster election. Part of his sensitivity comes from the likelihood that he will be thrown out of office, thus becoming, ignominiously, the first Prime Minster in recent times to have never won an election. The other reason for his sensitivity is that he dithered about holding an election in 2007 when he briefly enjoyed a period of popularity after taking over from the increasingly unpopular Tony Blair. Having lost his nerve in 2007 and been mercilessly criticised for it ever since, Brown is unwilling to risk a repeat.

But his problem is that he must hold a Westminster election by May 2010, no more than five years after the last (5 May 2005), and so he cannot wait or too long in the hope that 'events' will turn in his favour.

Politicians generally refer to hold election at times when people feel good about their lives – spring and early summer, for example. Elections in autumn or winter are avoided, as the mood of the electorate may be more negative as the nights draw in and the temperature (and the rain) falls.

So the two optimal times for Brown to call the election are spring this year or spring next year. Next year would be a big risk, because if the economy does not bounce back, then he would be forced to fight an election under very unfavourable circumstances.

At present Brown is basking in the reflected glory of his recent hosting of the G20 in London, and the presence of the new global superstars, Barack and Michelle Obama. If the promises and aspirations of the G20 do not immediately turn to dust, Brown might seize the moment to call a general election. Already the opinion polls have noticed a narrowing of the gap between the Labour Party and the Conservative Party, but unfortunately for Brown, the Tories are still ahead – 41% to 34%. Nonetheless, this may be as good as it will get for Labour, and Brown may decide to risk it, especially if he can find some 'green shoots' to boast about.

So, if Brown takes the plunge, when might it be?

This summer will see the election for the European Parliament on 4 June, and it may suit Brown to hold a simultaneous election for Westminster. Such a move would increase the turnout for the European election, which risks sinking to an embarrassing level in Britain with only the diehard Eurosceptics bothering to vote. But Brown's main preoccupation would be his survival as Prime Minister, and the European election would contribute nothing to that, and may instead allow too great a platform to his ideological opponents. So he may prefer to separate the two elections by a month or so. This could mean a Westminster election in early May – either 7 May or 14 May. The Early May Bank Holiday falls on 4 May, and so there may be a residual feeling of goodwill amongst those who still have jobs, that Brown may feel he can benefit from.

If Brown decided to plump for 7 May, when would be the latest date on which he could announce the election? The minimum timetable, excluding public holidays, between the dissolution of the Parliament and the date of the election is 18 working days. Counting back from 7 May, excluding the public holidays on 4 May, and 10 and 13 April, would require Brown to make the announcement this week, on 9 April.

If he decided to hold the election on 14 May the latest date of the announcement would be 20 April.

So the next few weeks will be of critical interest. If no announcement is made, then Brown will either have to risk an autumn or winter election, or try to cling on till the very last possible date, in spring 2010.

From the narrower perspective of Northern Ireland, all of these possibilities have consequences. An early Westminster election would clear some of the air and allow a recalibration of the strengths of the parties. If it saw the humiliation of the TUV, then this would bring forward Peter Robinson's long awaited discovery of unionist 'confidence' and the devolution of policing and justice. It may also destroy the shaky UCUNF structure, and lead to its dissolution, and the consequent demise of the UUP. When the dusk clears, it could see Northern Irish politics restructured into two dominant parties – the DUP and Sinn Féin. If there is no early election, then tempers and nerves might start to get frayed, especially if the TUV does unexpectedly well in the European election.

As always, the future is uncertain and some of the major influences on the stability of the Northern Irish political structures are external. Northern Ireland will play no part in Brown's decision-making, but his actions will have enormous consequences in Northern Ireland.