On April 11 Colonel Thompson arrived at New York.
Four days afterwards Sir H. Clinton wrote to General Leslie: ‘Those parts of your letters to which you have referred for a more full explanation to Lieutenant-Colonel Thompson, I shall answer after consulting with him upon the subject;’ and he also says: ‘With respect to the disagreeable predicament which you mention Lieutenant-Colonel Balfour and other officers of rank in the Southern army stand in on account of Mr. Green’s threats for Colonel Hayne’s execution, I shall consult Lieutenant-Colonel Thompson, and let you know my sentiments by the earliest opportunity.’
At this time Sir H. Clinton was about to give up the command he had so often petitioned to resign. He had ‘lamented that his happiness was sacrificed to prevent the partial inconvenience which might have arisen from a change,’ and later he wrote: ‘His Majesty’s assent to my petition will crown the many favours of which my heart will ever retain the most grateful remembrance.’
On February 6 General Robinson was appointed to succeed Sir H. Clinton, and soon after Sir Guy Carleton took the command.
Colonel Thompson’s chief business was to complete his regiment, which was encamped about three miles from Flushing, in Long Island. There, on August 1, colours were presented to the regiment by Prince William, then a boy of eighteen in the Royal Navy, accompanied by Admiral Digby. On the 6th, on behalf of himself and the officers of the King’s American Dragoons, Colonel Thompson petitioned Sir Guy Carleton to order them to enjoy the advantages stipulated on the completion of the regiment; and at the end of August Sir Guy Carleton notifies in the general orders that Colonel Thompson and his officers are entitled to permanent rank in America.
In September Colonel Thompson’s name is to be found first on a list of six agents, selected to act for them by those Royalists who were willing to emigrate with their families from Long Island to Nova Scotia.
Two months later it appears, from a bill, that he was building chimneys in the barracks at Huntingdon, Long Island, where his regiment was stationed, when the treaty of peace between America and England was made in Paris without the consent and even without the knowledge of France.
In December every preparation was made for a sudden attack of the French upon New York, and orders were issued by General Robinson in case that event took place. Alarm posts for each of the different corps and the details of the duties of each corps were arranged. ‘If an attack was made on Huntingdon, the troops were immediately to assemble and march to the support of Colonel Thompson.’