This weekend sees the return of the popular Tolpuddle Martyrs Festival, with music, film, talks and entertainment topping a packed programme.

But just who were the Tolpuddle Martyrs?

Life for farm workers in the 1800s was tough, and in 1833 a trade union was formed in West Dorset. Unions were legal at the time - but six leaders from Tolpuddle were later arrested and charged with taking a secret oath.

When word spread of what had happened to the Tolpuddle Martyrs, protests erupted throughout the country. Trade unionists consider the event the foundation of their movement.

Timeline of events

October 1833: The Friendly Society of Agricultural Labourers is formed in Tolpuddle, with George Loveless as its leader.

February 24, 1834: George Loveless and five others are arrested at their homes in Tolpuddle. They were charged with having participated in the administration of an illegal oath and marched to Dorchester.

March 1: The six farmworkers are interviewed and committed for trial at the next assizes. George Loveless was later visited by a lawyer, Mr Young, who promised him freedom if he would betray his companions. He refused.

March 4: Home Secretary Lord Melbourne said in a letter to landowner Squire Frampton that he did not want to ban unions as it would make martyrs of the Tolpuddle six.

March 21 and 22: The trial takes place at Shire Hall, Dorchester.

April 21: Up to 100,000 people attend a protest against the sentences at Copenhagen Fields in London

May 17: George Loveless is taken in chains aboard the William Metcalfe sailing from Portsmouth and bound for Australia.

June 1835: Lord John Russell, the new Home Secretary, grants conditional pardons for all six men. They refused this offer of compromise.

March 14 1836: After more pressure, the Government grants full and free pardons for the farm workers.

June 13, 1837: George Loveless returns home to Tolpuddle.