Although his father was initially reluctant to encourage his son in his choice of career – knowing from personal experience the potential financial hardship involved – he was won over by William's obvious talent, and funded a sketching trip to Wales, which proved to be an invaluable training ground.
In 1816 Havell was engaged in painting a series of pictures called 'Picturesque Views and Characteristic Scenery of British Villas', when he was appointed to the post of draughtsman with Lord Amherst's embassy to China.
[2] On his return he rejoined the Watercolour Society, but found that his work was not as popular as it once had been, and after a while be ceased to contribute to their exhibitions and took to painting in oils instead.
Although his works were of great merit and distinguished by pure and delicate colour, they failed to attract the public, and having lost his savings by the failure of an Indian bank, he became a pensioner on the Royal Academy's Turner Fund.
Havell died, after some years of declining health, at Kensington, London, on 16 December 1857, and was buried at Kensal Green Cemetery.
Havell was one of the best of the earlier painters in water-colour, and did much to advance this art, and his pictures in oil, though neglected during his lifetime, have risen greatly in estimation.