Socialism in the United Kingdom is generally thought to stretch back to the 19th century from roots arising in the aftermath of the English Civil War. Notions of socialism in Great Britain have taken many different forms from the utopian philanthropism of Robert Owen through to the reformist electoral project enshrined in the birth of the Labour Party.
The Reformation occurred later in Britain than in most of mainland Europe. As in the rest of Europe, various liberal thinkers such as Thomas More became prominent, but another important current was the emergence of the radical Puritans who wanted to reform both religion and the nation. The Puritans were oppressed by both the monarchy and by the established church. Eventually these pressures exploded in the violent social revolution known as the English Civil War, which many Marxists see as the world's first successful bourgeois revolution.
After the war several proto-socialist groups emerged. The most important of these groups were the Levellers, who advocated electoral reform, universal trial by jury, progressive taxation and the abolition of the monarchy and and of censorship. This was strongly opposed by Oliver Cromwell's government, who also persecuted the moderate reformist group the Fifth Monarchy Men and the radical utopian group the Diggers.