Costa Cabral, who became count of Thomar in 1845, ruled despotically, despite many insurrections, until May 1846, when a coalition of Miguelites, Septembrists and Chartist malcontents drove him into exile.
While in this phase he wrote his novels Yeast and Alton Locke, in which, though he pointed out unsparingly the folly of extremes, he certainly sympathized not only with the poor, but with much that was done and said by the leaders in the Chartist movement.
By this coup d'etat the constitution of 1822 was substituted for the charter of 1826; and a Septembrist ministry under the Viscount Sft da Bandeira replaced the Chartist ministry under Saldanha, Terceira and Palmella.
Kennington Common, now represented by Kennington Park, was the site of a gallows until the end of the 18th century, and was the meeting-place appointed for the great Chartist demonstration of the 10th of April 1848.
A counterrevolution, planned in the royal palace at Belem and hence known as the Belemzada, was frustrated in November 1836; and in 1837 a Chartist insurrection was crushed after severe fighting.
He took an active part in the Chartist agitation, but withdrew his support when the agitation for the repeal of the corn laws was removed from the Chartist programme.
In 1837 he established the Northern Star newspaper at Leeds, and became a vehement advocate of the Chartist movement.
In 1847 he was returned for Nottingham, and in 1848 he presided at a Chartist demonstration on Kennington Common, which caused great alarm (see Chartism).
On the r4th of June Mr Attwood, M.P. for Birmingham, presented to the House of Commons a Chartist petition alleged to have been signed by 1,280,000 people.
In 1840 Campbell conducted the prosecution against John Frost, one of the three Chartist leaders who attacked the town of Newport, all of whom were found guilty of high treason.