Although there is no statutory requirement for Westminster elections to be held on any particular day of the week, it has been the convention since 1935 that they are held on a Thursday. This means that there are now exactly 18 possible election dates, as Thursday 3 June is the last realistic day upon which the election could take place.
Since the election timetable is a formal one, starting on Day 0 – the dissolution of the existing Parliament – and finishing on Day 17 – Polling Day – it is possible to count backwards from the 18 possible polling days to calculate the 18 corresponding dates of dissolution. Account must be taken during this calculation iof the fact that Saturday, Sunday, Good Friday, other bank holidays and any day 'appointed for public thanksgiving or mourning' are disregarded. In practice this excludes 17 March (St. Patrick's Day), 2 and 5 April (Good Friday, Easter Monday bank holiday), and 3 and 31 May (bank holidays). The whole procedure is also frozen for 'days of mourning' if any member of the British royal family dies, but these cannot be included in the present calculation (it is worth noting, in passing, though, that Elizabeth Windsor will be 84 years old in April, and her husband Philip is 88).
Although it has been the custom for much of the twentieth century to 'prorogue' the Parliament before its dissolution, it is not a requirement and dissolution may occur at any time; the Parliament does not need to be sitting, or to be recalled, for the purpose of dissolution. This leaves the date for launching the electoral timetable quite open, and allows the British Prime Minister to get the Queen to dissolve the Parliament on any day of his choice.
The 18 possible 'dissolution' dates stretch from next Tuesday, January 12 (for an election on 4 February) until 10 May (for an election on 3 June). As each day passes without a dissolution it increases the probability that it will happen on one of the shrinking number of future possibilities. At the moment most people expect the election to take place in May, with 6 May being the favourite date. This would allow the Easter holidays to be over before the timetable starts. The dissolution for a 6 May election would take place on Monday 12 April. An April election, because of the early Easter, is seen as less likely, but some expect a surprise election in March.
The table below summarises the 18 possible election dates along with their corresponding dissolution dates:
Clearly some dates seem inauspicious, and although politicians may not be superstitious they will not want to offer the media any opportunity for ridicule. An election on April 1 can therefore be ruled out. It is unlikely that the election would fall on 8 April either, as the week following Easter is a popular holiday period.
Those for whom the date of the election is of interest (i.e. all those in political parties, who may be called upon to campaign, distribute leaflets or erect posters) it may be interesting to keep a close eye on the movements of Gordon Brown on the 'dissolution days' shown above.
For those who wish to know more, full details of the electoral process is available here.