Leading article: There is no case for delay over electoral reform

Opponents of the referendum on electoral reform continue to clutch at straws. As Parliament broke up for the summer recess yesterday, 44 Conservative MPs signed a motion arguing that the referendum should not be held on the same day as elections next May in Scotland, Wales and in parts of England. The dissenters claim the combination could distort the result of the poll on the Alternative Vote.

The argument is an unconvincing diversion. Voters are capable of giving separate verdicts on a parliamentary or local election and a referendum. The fact that some voters will have more reasons to head for a polling station than others is a factor that could work either way in relation to the outcome of the referendum. The truth is that the Tory dissenters are opposed to a change in the voting system, disapprove of the referendum pledge that David Cameron made to Nick Clegg as part of the coalition deal and are wary of the partnership with the Liberal Democrats in ways that extend well beyond this particular concern.

Mr Cameron should not lose very much sleep over this and nor should Mr Clegg. The numbers involved are relatively small. Most Conservative MPs appear willing to support the bill that would clear the way for a referendum next May even though they oppose electoral reform. For Labour, the Miliband brothers, one of whom will almost certainly be the next leader of the Labour party, have declared in favour of the Alternative Vote. The right of the Conservative Party and its unofficial leader, David Davis, might regard the Government led by Mr Cameron and Mr Clegg as the "Brokeback Coalition", but they are the ones that look increasingly broken in terms of their capacity to shape events, at least in the short-term.

The argument for a referendum next May is irrefutable. The legislation can be passed by then and the logistics are easily arranged. There is no point in holding the referendum at a different stage in the year and there is no obvious democratic purpose in doing so. The following autumn, days will be shorter. The spring of the year after will be dominated by another set of local elections. After that there would be no time to introduce a new voting system before the next general election. Attempts by Conservative MPs to block the referendum being staged next May should be dismissed by their colleagues on the Tory benches and by Labour MPs who were elected pledging to hold a vote on electoral reform. The agreed date is the right one.