Whitbread was a reformer – a champion of religious and civil rights, for the abolition of slavery, a proponent of a national education system and, in 1795, sponsor of an unsuccessful bill for the introduction of minimum wages.

After Fox's death, Whitbread took over the leadership of the Whigs, and in 1805 led the campaign to have Viscount Melville impeached.

Throughout the Peninsular War he played down French defeats convinced that sooner or later Napoleon would triumph, and he did all he could to bring about a withdrawal of Britain from the continent.

Whitbread began to suffer from depression, and on the morning of 6 July 1815, he committed suicide by cutting his throat with a razor.

[8] The Hammonds comment that "Whitbread is a politician to whom history has done less than justice... His most notable quality was his vivid and energetic sympathy; he spent his life in hopeless battles and died by his own hand of public despair.