[1] Townshend was elected to the House of Commons in 1754 as Whig member for Whitchurch in Hampshire, and held that seat till his elevation to the peerage in 1783.

During the ministry of Lord Chatham and the Duke of Grafton he supported the position his cousin Charles Townshend was in with regard to the American revenue program.

[2] Townshend remained in opposition until the end of Lord North's ministry and spoke frequently in the House of Commons against the American Revolutionary War.

A memorandum which Shelburne wrote to him at this time listing matters requiring his urgent attention said: "Preparations and Plans for W. India [Spanish America].

[4] The plan drawn up by Phillip and approved by Townshend in September 1782 was for a squadron of three ships of the line and a frigate to mount a raid on Buenos Aires and Monte Video, from there to proceed to the coasts of Chile, Peru and Mexico to maraud, and ultimately to cross the Pacific to join the British East Indian squadron for an attack on Manila, the capital of the Spanish Philippines.

Phillip took the Europe to India to join the British East Indian squadron, but after his return to England in April 1784, remained in close contact with Townshend (now Lord Sydney) and the Home Office Under Secretary, Evan Nepean.

From October 1784 to September 1786 he was employed by Nepean, who was in charge of the Secret Service relating to the Bourbon Powers, France and Spain, to spy on the French naval arsenals at Toulon and other ports.

Following the loss of the Thirteen Colonies, Sydney, as Home Secretary in the Pitt Government, was given responsibility for devising a plan to settle convicts at Botany Bay.

In choosing the name "Sydney" when he was raised to the peerage in 1783, Thomas Townshend demonstrated his pride in descent from the Sidney family, who had been eminent opponents of Stuart absolutism.

It is probable that Sydney was aware of his distinguished ancestor, Algernon Sidney's characterisation of the founders of imperial Rome: “Thus we find a few Men assembling together upon the Banks of the Tiber, resolv’d to build a City, and set up a Government among themselves”.

Sydney was buried in the Scadbury chapel in the parish church of St Nicholas's in Chislehurst in southeast London, where a large memorial tablet to him may be seen.

[citation needed] He did not support the American Revolution but was a strong opponent of the war which he thought was pointless and needlessly prolonged during Lord North's ministry.

Alan Atkinson wrote in The Europeans in Australia (Oxford University Press, 1997): "Townshend was an anomaly in the British Cabinet, and his ideas were in some ways old-fashioned...