Last night in the Lords, the government’s Electoral Registration and Administration Bill was amended, to delay the planned boundary review of Commons constituencies (which was previously agreed in the Parliamentary Voting System and Constituencies Act 2011). In short, this was the Liberal Democrats wreaking their revenge on the Conservatives for the collapse of Lords reform. 72 Lib Dem peers voted in favour of the amendment, and it passed by 300 votes to 231.

This is undoubtedly a major blow for David Cameron and his Conservative colleagues. But was it a government defeat? The Independent reports it as a ‘bruising defeat on the Government’, but the Guardian more cautiously avoids using the D word in this way, only suggesting that should Cameron try to reverse the decision in the Commons he ‘would be defeated’, while the BBC makes no mention of the word at all.

For those of us who monitor parliamentary voting, this episode presents a dilemma. While commentators can skirt around the word, we need to decide whether this was a government defeat or not. The Constitution Unit’s website has long provided a breakdown of government defeats in the House of Lords as they happen, but this doesn’t quite fit the category. While the Conservatives whipped in favour of keeping the legislation as it was, the Liberal Democrats whipped against. Those voting for the amendment included Lib Dem ministers. Party leader Nick Clegg had made clear his intention to scupper the proposals when Lords reform was dropped, and defended his peers’ decision today, as the BBC story reports. This was clearly not a government win, and nor was it a free vote, but when the Deputy Prime Minister himself is applauding the decision, it can hardly be described as a defeat either.

Like us, the House of Lords authorities keep a running total of government defeats. Their own website chooses to describe this as a government defeat, on the basis that the government Chief Whip acted as a ‘teller’ for those wanting the bill to stay as it was. But the Liberal Democrat Chief Whip (who is also the government Deputy Chief Whip) was among those voting for it to change. I do not criticise the decision of the House of Lords’ authorities: they had to decide very quickly which way to jump. The support of the government Chief Whip is normally a pretty definitive indicator of the government’s position. But we are now in new territory, where the government – at least on certain matters – has no unified position. It seems that we need a new category for such parliamentary decisions. We have chosen for now to call this a ‘coalition split vote’. Comments and alternative suggestions are welcome below. It would be particularly interesting to know how such episodes are viewed in other jurisdictions more familiar with coalition government. The British are novices at this stuff.

This peculiar episode illustrates two more interesting things: the first is how little attention the media pays to the House of Lords. Had Liberal Democrat ministers gone through the division lobbies against their Conservative colleagues in the Commons this would have been huge political news. But because it occurred in the Lords, it didn’t even make last night’s BBC headlines. The second interesting factor is why this didn’t happen in the Commons. Cameron does not have the numbers in the Commons to overturn the decision, so it is not just a numbers issue, and he is unlikely to overturn the decision. But the second chamber’s culture of ‘self-regulation’ was crucial to this vote. The clerks’ official advice had been that the amendment was ‘inadmissible’ because it was ‘not relevant to the bill’. But peers decided to vote for it anyway. In the Commons such an amendment would have been ruled out of order by the Speaker and MPs would have been denied a chance to vote on it. In the Lords, all poor Leader of the House Lord Hill of Oareford (who has only been in post for a week, following Lord Strathclyde’s resignation) could do was plead with peers to follow convention (see here, column 490).