A former veteran Tory whip texts:

“There have been 2,000 pairs arranged since the General Election. 66 have been broken. 14 pairs have been broken by the Government and 52 pairs have been broken by the Opposition (of which 7 were broken by the Lib Dems, despite them having only 12 MPs). There is a lot of faux outrage about.”

It turns out Labour, and proportionally especially the LibDems, are by some distance the worse offenders when it comes to breaking pairs. It does seem to happen a fair amount – around 3% of pairs are broken, and four-fifths of the broken pairs were committed by opposition parties. The Brandon Lewis / Julian Smith / Jo Swinson row comes down to whether you believe the chief whip that it was a mistake… it would be an extraordinarily dangerous thing to lie about…