William Oliver was a building surveyor who, as a result of an unpaid debt, was sent to Fleet Prison in May 1816. While in prison Oliver was recruited as a Home Office spy. Once released, Oliver became friends with Charles Pendrill, a radical shoemaker who had been a known associate of Colonel Edmund Despard, the leader of a gang who had been executed in 1803 for plotting to kill George III.
Pendrill introduced Oliver to Joseph Mitchell and in April 1817 the two men travelled to met leading reformers in the industrial districts. On 4th May, Mitchell was arrested by the authorities and sent to Cold Bath Fields Prison. Oliver continued his journey and began informing the reformers that Radicals in London were planning an armed uprising in London on 9th June and asked them to organise local workers to join the rebellion. This was untrue and it is now believed that Oliver was working as an agent provocateur for Lord Sidmouth, the Home Secretary.
On 4th June Oliver was seen by a reformer in Wakefield conversing with a man who worked for Major-General John Byng, the army commander of the Northern District. Word was quickly sent out to all reforming groups that Oliver was setting a trap. However, some of the radicals did not receive the information and on 9th June, Jeremiah Brandreth, led 300 men on a march on Nottingham. Brandreth told his followers that hundreds of thousands of men all over England were rising that day. Brandreth was wrong and he was quickly arrested by the army when he approached the city.
Thirty-five of the men were charged with high treason. Brandreth and two others were sentenced to death and another eleven men were transported for life. The men were originally sentenced to being hung, drawn and quartered, but the quartering was remitted. On the scaffold one of the men shouted out that they were victims of Lord Sidmouth and Oliver the Spy. Edward Baines of the Leeds Mercury investigated their claims and was able to find enough evidence to implicate the government in the conspiracy. In his article exposing William Oliver, Baines described him as a "prototype of Lucifer, whose distinguishing characteristic is, first to tempt and then to destroy."
I went to Jerry Brandreth's between six and seven this evening. We left his house and met Stevens and walked up Sandy Lane. Stevens said I should have been here on Monday night. He stated that there was a London Delegate, who reported that there was about 70,000 in London ready to act with us; and that they were very ripe in Birmingham.
On the 1st or 2nd of June, Oliver came to Nottingham. He said, that all would be ready in London for the 9th June. Oliver had a meeting with us now, at which meeting Brandreth and Turner, and many others were present. At this meeting he laid before us a paper which he called a plan of campaign. When Oliver had thus settled everything with us, he prepared to set off to organise things in Yorkshire, that all might be ready to move in the country at the moment that the rising took place in London, where he told us there were 50,000 men with arms prepared, and that they would take the Tower of London.
Oliver drew towards London, leaving his victims successfully in the traps that he had prepared for them. The employers of Oliver might, in an hour, have put a total stop to those preparations, and have blown them to air. They wished, not to prevent, but to produce those acts.
The employment of spies on the part of government had done as much to produce a change of opinion as the harsh exercise of authority. There might have been some credit reflected on the government by their prevention of the projected mad march of the blanketeers on London, by their putting down the insurrection in Derbyshire, and by their suppression of the rising in Scotland, which resulted in the capture of the rebels at Bonnymuir; but it was known that Oliver, a paid government agent, had counselled the blanket meeting and the Derbyshire outbreak, and in Lancashire it was well known that representations of the country being ripe for revolt, which occasioned the rising in Scotland, were the work of spies; that although it was to have been simultaneous, not one, even of the most foolish and rash Lancashire men gave credence for a moment to the government agent; and an incendiary placard, posted in Manchester on the 2nd of April, calling on the people to effect a revolution by force was laughed to scorn. Even the wicked conspiracy of Thistlewood and his confederates to assassinate the king's ministers at a cabinet dinner, had no effect in exciting sympathy in favour of the latter, for there was the strongest evidence to prove that Edwards, a government spy, was the originator of the scheme, and that he had provided the arms with which the murders were to have been effected.