The statutory immunity of trade unions from liability for inducing breach of contract when calling on members to come out on strike or to take other industrial action depends on the union having the support of a ballot. Further, whenever they undertake a ballot concerning proposed industrial action trade unions must give at least seven days notice to the employers of all members entitled to vote, complying with the specific requirements set out in TULRCA 1992 ss.226, 226A and 234A, Failure to comply with these requirements will mean that the unions concerned will forfeit their statutory immunity (see notes at Trade union matters/immunity from civil action in certain cases ). This happened to the Union of Construction Allied Trades and Technicians in a High Court case heard in November 2003 in which Willerby Holiday Homes Ltd won £130,000 damages from UCATT after that union had failed to give the required seven days formal notice of its intention to ballot, did not correctly ballot everyone in the union and did not give the statutory seven days' notice before bringing members out on strike (note in Contract Journal on Willerby Holiday Homes Ltd v UCATT, Dec 2003).

The requirements are strictly construed. A union must do everything which could reasonably be required of it to ensure that all relevant members get ballot papers (see National Union of Rail, Maritime and Transport Workers v Midland Mainline Ltd [2001] EWCA Civ 1206, Court of Appeal on 25th July 2001, reported at [2001] IRLR 813, CA). Also the union has the obligation to give the employer(s) information as to numbers of members in particular grades and at particular workplaces (see London Underground Ltd and ors v National Union of Rail, Maritime and Transport Workers Court of Appeal on 16th February 2001. In October 2009 the same union's failure to provide EDF Energy Powerlink Ltd with adequate information about employees entitled to vote in a ballot led to the High Court granting an injunction which led to the calling off of an imminent strike on the London Underground ( EDF Energy Powerlink Ltd v National Union of Rail Maritime and Transport Workers HC 2009 EWHC 2852 on 23rd October 2009.

Trade union members have the right to object if their union induces them to take part in industrial action which does not have the support of a ballot (TULRCA 1992 s.62).

Until 1st April 1996 trade unions could have the legal right to financial assistance from the government for balloting members on specified issues and also the right to require an employer to permit premises of his to be used to give union members a convenient opportunity of voting. These rights ceased with effect from 1st April 1996 (with a six month "mop-up" period which ended on 30th September 1996).

Two new Codes of Practice (on "Industrial Action Ballots and Notice to Employers") came into force on 1st October 2005 (see the Employment Code of Practice (Industrial Action Ballots and Notice to Employers) Order 2005, SI 2005/2420 and the Employment Code of Practice (Access and Unfair Practices during Recognition and Derecognition Ballots) Order 2005, SI 2005/2421). The latter makes detailed changes to the rules under which industrial action is regarded as not having the support of a ballot (TULRCA 1992 ss.232A and 232B). There is a useful summary on a Direct Gov web-site on Industrial Action Ballots.

See also notes at Trade union matters/industrial action and/or Trade union matters/recognition .