We’ve learnt this year that if an MP defects – particularly to UKIP – people pay attention. With their high-profile defections causing two by-elections, Douglas Carswell and Mark Reckless sparked both parliamentary panic and media meltdown.

But sometimes parliamentarians defect without anyone even noticing. It has, in fact, happened a lot more regularly in the House of Lords.

Carswell and Reckless symbolically crossed the floor of the House of Commons from government to opposition benches when they quit an established party to join a newcomer. But it can be much harder to be certain about the party allegiances of peers.

The House of Lords effectively has three sides. There are not just government and opposition benches, but also cross-benches. There are currently 176 cross-bench peers, organised to some extent as a group, but not taking any party whip. They include Lord Birt, the former BBC director general, Baroness Boothroyd, the former speaker of the House of Commons and Lord Condon, the former Metropolitan Police commissioner.

There are also 24 senior Church of England bishops in the House of Lords at the moment. They do not belong to any political party or grouping and are not considered to be cross-benchers either. Peers do not have to stand in general elections under a party banner or send out material to constituents. Many lords rarely attend parliament and do not hold ministerial or party office, so there can be little evidence of their party allegiance, even if they have one.

Wind them up and watch them go

Lord Pearson leapt ahead of his MP colleagues.PA

Sometimes when lords go a-leaping from one party to another they do cause a bit of a stir. Several peers defected from the Conservatives to UKIP long before most people had even heard of Mark Reckless and Douglas Carswell. They were Lord Willoughby de Broke in 2007, Lord Stevens of Ludgate in 2012 and Lord Pearson of Rannoch. Rannoch joined UKIP in 2007 and served as party leader for a year. During the 2010 election, it was he who famously admitted that he had not actually read all of his party’s manifesto.

Other defections go unnoticed. Lord Trimble, the former Ulster Unionist Party leader, is now a Conservative member of the House of Lords, although the two parties are now separate.

Robert Munro was a particularly interesting case. He was a Liberal MP until 1922 then went to the House of Lords as Baron Alness, the change of name making his career harder to follow. Eventually in 1945, he appeared in Churchill’s Caretaker Government, suggesting that he considered himself a Conservative, although he never announced a change of party allegiance.

Then there are peers with hereditary titles, where succeeding generations take a different party whip from their forebears. Conservative prime minister Stanley Baldwin went to the Lords on his retirement, but his son Oliver, who became the second Earl Baldwin, took the Labour whip. The current (fourth) Earl Baldwin is a cross-bencher.

In the opposite direction, the current Lord Attlee, grandson of Labour prime minister Clement Attlee, is a Conservative. Viscount Tenby, grandson of Liberal prime minister Lloyd George and son of a Conservative peer, is a cross-bencher. Lord Trefgarne is a Conservative peer, although he is the son of George Garro-Jones, who was a Liberal, then Labour, then a Liberal again. Viscount Simon, a Labour peer, is the grandson of the first Viscount, who was a Liberal and later a Liberal National politician.

So these ten lords went a-leaping, but most of them leapt in the dark. Hardly anyone noticed. We should pay attention to leaping lords, because they can show us which way the wind of political defections is blowing. Where lords leap now, MPs may later follow.

Alun Wyburn-Powell is a member of the Liberal Democrat Party, but not an elected representative or office-holder.