Where do trade unions stand on the EU referendum?
The voice of big business has been heard in the EU referendum campaign, but there has been less said about the workers.
In the 1975 referendum on EEC membership, the trade unions were in favour of leaving. In 2016 more, but not all, of them are urging their members to vote to remain in the EU.
Daily Politics reporter Adam Fleming looks into the archives to find out what has changed.