Sir Thomas, who is described by contemporary chroniclers as a noble and wise knight, met the leading conspirators at dinner with the Abbot of Westminster on 18 December 1399, and there they agreed to surprise Henry at a tournament at Windsor.
But Henry discovered the plot through the treachery of the Earl of Rutland, and, summoning an army in London, advanced against the rebels, who had assembled in some hundreds near Windsor.
He was first hanged, then cut down and eviscerated, although still alive and replying to the taunts of Sir Thomas Erpingham, the king's chamberlain, who directed the horrible procedure; he was finally beheaded and quartered, and his head was sent to London.
His large estates were forfeited to the crown, but some were bestowed on Sir Walter Blount (d. 1403), a distant relative, and his wife Sancha.
One contemporaneous account read: His death is mentioned in Shakespeare's play Richard II in the final act when Northumberland enters to tell King Henry "The next news is, I have to London sent.