The fugitives did not hurry themselves when they reached town. On the evening of their arrival, it was afterwards discovered, the elder purchased a pair of shoes at a shop in Oxford Street, paying for them with a £10 Bank of England note. They employed their time in London in a shopping campaign, purchasing largely and always tendering bank-notes, with the object of accumulating a large sum of money in gold, by way of change.
At the end of this week they procured a horse and gig and left London, saying they intended to travel to Ireland. Meanwhile, the loss of so many bank-notes had been widely advertised and the good faith of persons who presented any of them for payment enquired into. The movements of the men who had stopped the driver of the mail-cart and robbed him were traced, and soon the Holyhead Road was lively with the pursuit of them.
They arrived at Knutsford, in Cheshire, only a short time before the coming of the mail-coach bringing particulars of the robbery. Before that, however, they had attracted a considerable deal of notice by their singular behaviour at the "George" inn, where they had put up. To draw attention by peculiarities of dress or demeanour is obviously the grossest folly in fugitive criminals, whose only chance of safety lies in unobtrusive manners and appearance. That would appear to be obvious to the veriest novices in crime. But the Beatsons were no doubt by this time agitated by the serious position in which they had irretrievably placed themselves, and in so nervous a state that they really had not full command of their actions. They adopted a hectoring manner at the inn, and on the road had attracted unfavourable notice by the shameful way in which they had treated their horse.
On the arrival of the mail containing the official notices of the robbery and descriptions of the two men concerned in it, the appearance of these two men with the gig seemed so remarkably like that of the robbers, that a Post Office surveyor was sent after them. They had already left Knutsford, and had to be followed to Liverpool, where they were discovered at an inn, and arrested.
The mere hasty preliminary inspection of their travelling valise was sufficient to prove that these were the men sought for. Bank-notes to the amount of £1,700 were discovered, wrapped round by one of the letters stolen; and the purchases of jewellery and other articles carried with them were valued at another £1,300.
Taken back to London, the prisoners were charged in the first instance at Bow Street, and then committed for trial at Horsham. An attempt they made to escape from Horsham gaol was unsuccessful, and they were found hiding in a sewer. Their trial took place before Mr. Baron Hotham on March 29th, 1802. No fewer than thirty witnesses were arrayed against them; chiefly London tradesmen, from whom they had made purchases and tendered notes in payment. There could hardly ever have been a clearer case, and the result of the trial was never for a moment in doubt.
The affectionate efforts of the elder man to shield his adopted son drew tears from many eyes, but the readiness of that "son" to take advantage of them and to throw the guilt upon him excited, naturally enough, much unfavourable comment. Two statements had been prepared and written by the prisoners, and both were read by the younger in court. The first was by John Beatson, who declared himself to be guilty, but his "son" innocent. Whalley's own statement, to the same effect, went into a detailed story of how his "father" had given him a large number of the notes, and had told him they were part of a large remittance he had lately received from India.
The story was so clumsy and unconvincing, and the story told by the prosecution so complete in every detail, that both prisoners were speedily found guilty. They were condemned to death, and were hanged on Saturday, April 7th, 1802, at Horsham, before a crowd of three thousand people. The elder Beatson was seventy years of age and the younger but twenty-seven.