There's a lot of nonsense being spoken about the supposed democratic disgrace of the unelected House of Lords voting against the elected Commons this afternoon. As it happens, they are only able to do so because the government has tried to escape scrutiny of the move to cut tax credits. The Tories are the authors of their own demise.

This happened in two ways. Firstly, they did not tell voters they wanted to cut tax credits before the election. In actual fact David Cameron came close to promising he wouldn't. It was not quite Nick-Clegg-standing-next-to-a-pledge level of hypocrisy, but it was pretty close. During the Question Time leaders' debate, he was asked about tax credits and child tax credits and said he wouldn't cut them. The extent to which he was talking about tax credits, rather than child tax credits, is unclear, but no fair-minded viewer would have emerged from the exchange with the impression he intended to cut either.

The Tories refused to go into any detail of their planned benefit cuts before the election - and for good reason. As they have seen, cutting tax credits for the lowest paid workers in the country is very unpopular. But had they put the cut to tax credits in their manifesto, there would have been nothing the Lords could have done to stop them. The Salisbury Convention prevents the Lords opposing the second or third reading of a bill which appeared in the governing party's manifesto. If the Tories had been honest with the public at the election, the Lords could not have rebelled against them.

They could also have prevented a Lords rebellion if they had put the tax credit cut in a bill. The Lords cannot vote against financial legislation. But the Tories didn't. They tried to sneak it in with a statutory instrument.

Statutory instruments mean you can quickly get a change to the law through parliament without the usual standards of debate and scrutiny. They are there to facilitate small changes in law which do not require much debate. But they have grown into a democratic menace, with governments regularly using them to sneak in substantial legal changes without submitting them to the will of parliament. But here's the good thing about statutory instruments: the Lords can vote against them. It's complex and nuanced and there's a lot of discussion around precedent (which you can read up on here) but it is doable.

If the government had been decent enough to put these cuts through as a bill, they wouldn't be in this mess. And they would also have the ability to introduce amendments addressing the concerns of their critics on the government and opposition benches. But they didn't. They tried to sneak it in. And now it has come back to bite them.

This error has sparked all sorts of nonsense from Downing Street. Government sources have said they're going to 'suspend' the Lords, which they do not have the power to do. They are either whipping up lies or their constitutional understanding is so precarious they must be considered functionally incapable of doing their job. They've also threatened to stuff the Lords with Tories to undo their lack of a majority. That would be welcome, because it would show once and for all how undemocratic they have become and how urgently in need of repair Britain's constitutional arrangements are.

It would be far preferable, however, if they learnt a different lesson: that they should be straight with the public and straight with parliament. Had they done so, they would not be in their current predicament.