I'm not sure that demonstrating that Major used prorogation to avoid scrutiny of a scandal really changes much. So we're agreed that PMs prorogue Parliament for abnormally long periods when they want to avoid awkward questions? Why might Johnson be doing that now? Why risk all of these negative headlines to avoid just four sitting days?

Of course, it's also absurd that Parliament has carried on with its usual summer and conference recesses as if nothing important is happening.