Date of the Castlereagh East by-election

After the DUP's failed attempt to co-opt a young woman with UDA connections to replace Iris Robinson on Castlereagh Borough Council, it is now inevitable that there will be a by-election.

Thanks to Jim Allister's ill-advised attack on the Chief Electoral Officer (also picked up by the News Letter), it is possible to sketch out the possible dates for the by-election.

Douglas Bain, the CEO, stated that "the law provides that the Notice of Election must be published within 21 days of 24 February, which was the date on which I was satisfied that a vacancy had occurred. That period expires on 26 March." The maximum period that can occur between the publication of a Notice of Election and the polling day itself is 28 days (excluding Saturdays, Sundays, public holidays and 'Maundy Thursday'). During the period in question there are four such excluded days: Maundy Thursday on 1/04/2010, Easter Friday on 2/4/2010, Easter Monday on 5/04/2010, and the Spring Bank holiday on 3/05/2010.

That brings the last possible date for the by-election to 11 May 2010.

However, if Mr Bain wishes, he could shorten some of the periods. If he waits until the expiration of the maximum period before publishing the Notice of Election, then this allows the election to take place on any date between 4 May and 11 May. If he publishes the Notice of Election before its maximum period the by-election could take place in the second half of April.

Why all of this matters is simple. It is widely expected that Gordon Brown will call the Westminster election for 6 May, and a by-election in the DUP's heartland before that date would act as the ultimate poll of public sentiment towards that party. If there was a by-election before the Westminster election it would show how damaged the DUP has been by the Iris Robinson scandal, and how much of its support has migrated to the TUV or the UUP. The outcome of such an election would have a colossal impact on a later Westminster poll, dealing a massive morale boost to one or other party. Impressions matter – if the TUV or the UUP are seen to be 'on the up' in Castlereagh it could boost their vote elsewhere. Conversely, if the DUP easily retained Robinson's seat, this would greatly boost their image in the Westminster election, and give them extra votes.

There are a number of possible outcomes. Perhaps Gordon Brown, watching his poll ratings rise, will choose to delay the Westminster election for as long as possible, and the Castlereagh by-election will have to take place first. Another possibility is that the Electoral Office will hold the by-election on Wednesday 5 May (by-elections are usually on a Wednesday), but will not count the votes until after the Westminster election, if this is held on 6 May. In this way the Electoral Office will be seen to have acted according to the word of the law, but yet will not have influenced the outcome of the Westminster election.