I first heard about the Tolpuddle Martyrs on Blue Peter. In the days of Valerie Singleton, John Noakes and Peter Purves, Blue Peter was a source of all sorts of interesting information which I still remember today.
It was 1834, just after the Captain Swing riots, and a group of men in Dorset decided to form a trade union to protest about their low wages - they were getting 6/- a week at that time. It was called the Friendly Society of Agricultural Labourers. Forming a trade union was legal - but they were arrested for swearing an illegal oath when they joined. The law that was used had actually been passed to deal with the naval mutiny of 1797, and had never been repealed. The jury at the trial was packed with landowners and magistrates who opposed the rights of working men to band together to negotiate a fair wage, and the six men were transported to Australia.
And then there was a public backlash against the severity of the sentence. Petitions were signed (with 800,000 signatures), there was a protest march - 30,000 people marching up Whitehall, and most of the men were freed and were able to return home.
There's now a Tolpuddle Martyrs Museum, and there's a festival in the village every year to commemorate the men, usually the third week in July - so just around now. People like Tony Benn and Billy Bragg have attended, because of the importance of the Martyrs to the history of the trades union movement. The website is www.tolpuddlemartyrs.org.uk