Employment Act 1980

The Employment Act 1980 (c. 42) is an act of the Parliament of the United Kingdom, passed under the first term of Margaret Thatcher's premiership and mainly relating to trade unions.

Overview
It restricted the definition of lawful picketing 'strictly to those who were themselves party to the dispute and who were picketing at the premises of their own employer'.

It also introduced ballots on the existence of closed shops, and at least 80% of the workers in a particular industry need to support them for their maintenance.