The Trades Union Congress is the umbrella group for trades unions in the UK.
About seven million workers belong to the 58 unions which are affiliated, although not every union is in association with the congress.
The TUC brings together the unions to draw up common policies, lobby government, campaign and represent British workers on international bodies in the EU and the International Labour Organisation.
The TUC's decision-making body is the annual congress, the unions' equivalent of a political party conference. For four days in September delegates from each affiliated union meet to discuss motions, which then form the basis of the TUC's work for the next year.
But between congresses, the TUC's 56-member general council, which meets every two months, takes the decisions. It is headed by the general secretary, Brendan Barber.
The first TUC was held in 1868 and the Labour Party later grew out of the trade union movement and a special conference called by the TUC.
The TUC is not affiliated to Labour itself and does not provide it with funds, although many of its affiliated unions do give large donations.
Senior ministers regularly make speeches and take questions on the platform and fringe meetings at the TUC.
Labour prime ministers tend to give the platform speech or address the TUC dinner during the week of congress.