Guillotines in London?
In the eighteenth century, the king of France was the real ruler of his country. There was no parliament to help make the laws. Many Frenchmen thought that this was wrong. In the Revolution which broke out in 1789 they demanded a share of power and fair rights for the people.
Men and women in Britain were shocked by the violence of the French Revolution. But some of them (called the 'radicals') were on the side of the French reformers. They thought that Britain also needed a good deal more freedom. They said that rule by king, lords, and gentry was unfair. They wanted all men to have the right to vote.
By 1792 most towns in Britain had radical clubs. But the news in 1793 turned the British people against the French. The king and queen of France were put to death in public on the guillotine in Paris. Hundreds of nobles and ordinary men and women came to the same end. Horror swept through Britain. Radicals, it was said, were the friends of murderers.
The outbreak of war with France in 1793 made things worse for the radicals. Now their enemies called them traitors as well. The government banned radical meetings, closed down their clubs, and arrested their leaders. They said that those who took the radicals' side wanted guillotines in the streets of London.
Walter Robson: Britain 1750 – 1900; Oxford University Press, 1993/2002, page 34