The Catholic delegates, with Tone as secretary, left for London four days after the Convention broke up. Contrary winds prevented them sailing from Dublin to Liverpool; so they crossed instead to Scotland, travelling – some thought unwisely – via Belfast. Arriving at 9 a.m. on 12 December, they breakfasted at the Donegall Arms with a number of prominent citizens and reformers. A great crowd outside chanted: ‘Success attend you! Union! Equal Laws, and Down with the Ascendancy’, and insisted on drawing their carriage across the Long Bridge on the road to Donaghadee. Though Tone scarcely figures in other reports of the mission, he was singled out for particular attention by the Belfast press, signifying his special prominence in the town.

As a token of their new dignity and firmness, the Catholic delegates had been instructed to adopt a determined tone with the London government and ‘to take an hotel, and make a superb appearance’. They accordingly took up residence in Grevier's Hotel, Jermyn Street, on their arrival in London and conducted their business ‘in great state, making a splendid appearance’. Keogh in particular looked ‘very grand and very vain’ in his silk stockings and curled and powdered wig. They were entertained lavishly by Lord Rawdon and assisted by a number of Irish reforming MPs then in London.

Through Knox they sought an audience with Abercorn, but were anxious not to give offence to ministers by openly visiting ‘other persons of consequence’. Knox therefore proposed a meeting at his own lodgings. But Abercorn objected to ‘anything which (however unjustly) might carry with it the appearance of clandestine proceeding on my part’, and insisted ‘that it must be perfectly understood that it is their desire to see me, not mine to see them’. The delegates accordingly called at his London residence on the 21st. What passed threatened to reduce the Catholics to the position of servile supplicants which they had spent the entire year surmounting. Abercorn represented them as having eagerly sought him out both in Ireland and England, attributed to them certain principles which they rejected, criticised them for not applying to the government in Ireland, and sent them away without any promise of support.