During the Civil War some radicals such as John Lilburne began writing and distributing pamphlets on soldiers' rights. He pointed out that even though soldiers were fighting for Parliament, very few of them were allowed to vote for it. Lilburne argued that all adult males should have the vote and that these elections should take place every year. Lilburne, who believed that people were corrupted by power, argued that no members of the House of Commons should be allowed to serve for more than one year at a time.
In 1645 John Lilburne, John Wildman, Richard Overton and William Walwyn formed a new political party called the Levellers. Their political programme included: voting rights for all adult males, annual elections, complete religious freedom, an end to the censorship of books and newspapers, the abolition of the monarchy and the House of Lords, trial by jury, an end to taxation of people earning less than £30 a year and a maximum interest rate of 6%.
The Levellers started publishing their own newspaper, The Moderate. They also organised meetings where they persuaded people to sign a Petition supporting their policies.
In 1646 Leveller supporters were elected from each regiment of the army to participate in the Putney Debates. The debate was based on An Agreement of the People, a constitutional proposal drafted by the Levellers. Senior officers in the New Model Army such as Henry Ireton argued against the idea of universal suffrage.
Others such as Thomas Rainsborough, a member of the House of Commons supported the demands of the Levellers. In the debate he argued: "that every man that is to live under a government ought first by his own consent be put himself under that government." A compromise was eventually agreed that the vote would be granted to all men except alms-takers and servants.
When these reforms were opposed by officers in the New Model Army, the Levellers called for the soldiers to revolt. In March 1649, John Lilburne, John Wildman, Richard Overton and William Walwyn were arrested and charged with advocating communism. After being brought before the Council of State they were sent to the Tower of London. Lilburne was tried first and after a jury refused to convict him the other Levellers were released on 8th November.
Oliver Cromwell agreed with some of the Leveller's policies, including the abolition of the monarchy and the House of Lords. However, he refused to increase the number of people who could vote in elections. Lilburne now began writing pamphlets attacking Cromwell's government. Cromwell responded by having John Lilburne arrested and imprisoned in the Tower of London. Over 10,000 people signed a petition calling for Lilburne's release but Cromwell refused to let him go.
Former members of the Levellers grew disillusioned with the dictatorial policies of Cromwell and in 1655 Edward Sexby, John Wildman and Richard Overton were involved in developing a plot to overthrow the government. The conspiracy was discovered and the men were forced to flee to the Netherlands.
In May 1657 Edward Sexby published, under the pseudonym William Allen, Killing No Murder, a pamphlet that attempted to justify the assassination of Cromwell. The following month he arrived in England to carry out the deed, however, he was arrested and imprisoned in the Tower of London.