Trade Union and Labour Relations (Consolidation) Act 1992

11 Exclusion of common law rules as to restraint of trade. E+W+S

(1) The purposes of a trade union are not, by reason only that they are in restraint of trade, unlawful so as—

(a) to make any member of the trade union liable to criminal proceedings for conspiracy or otherwise, or

(b) to make any agreement or trust void or voidable.

(2) No rule of a trade union is unlawful or unenforceable by reason only that it is in restraint of trade.