There is an alternative and more plausible explanation for the Gunpowder Plot (“The plot that never was”, 30 October) That is, there was a plot, but the Earl of Salisbury learnt about it in advance and was able to use it to manipulate King James I into imposing further repressive measures against Catholics.

The crucial piece of evidence for the existence of a plot centres on the gunpowder itself. After the “discovery” of the plot, the Tower of London recorded receiving a quantity of gunpowder discovered below the House of Lords: this receipt was published in the Bulletin of the Institute of Historical Research by N.A.M. Rodger in 1980. Furthermore, this gunpowder was “decayed” in the contemporary expression, that is the various elements which made it up had separated.

This is the evidence that there was a plot, the gunpowder having been placed there by Guy Fawkes, an English Catholic mercenary who came over from Flanders. But it is also evidence that Salisbury knew about it. He was probably tipped off about the plot roughly ten days before the “discovery”, and at some point must have satisfied himself by organising a secret inspection that neither the King nor anyone else was in actual danger.