A trade union that calls members out on strike is in principle inducing employees to break their contracts of employment. However, it will not be liable for inducement if it complies with complex rules surrounding ballots for industrial action. In particular, a union has got to give an employer a list of the categories, numbers and workplaces of the employees who are entitled to vote in the ballot. In British Airways plc v BALPA, the airline's attempt to get an injunction to prevent a strike failed because the union had done enough to comply with its obligation to provide information.

BALPA balloted its members about whether to take industrial action in relation to a trade dispute. It gave the airline information about how many employees were entitled to vote, broken down by position (such as Captain or First Officer) and the numbers employed at Gatwick and Heathrow. The airline argued that this was not sufficient information to allow it to make plans for dealing with potential industrial action. To plan effectively, it needed to know how many employees in its long haul and short haul fleets were going to be balloted and the union had failed in its information obligation by not providing that breakdown.

The High Court and Court of Appeal rejected the airline's application for an injunction to prevent the strike. The union had to provide information about the "categories" of employee being balloted. That was a broad and flexible concept that had to be assessed in a common sense and practical way, reflecting the dual objectives of the legislation. Those were the need for employers to take steps to mitigate the impact of strike action, while not placing too great a burden on unions, or placing hurdles in the exercise of rights to take industrial action. In this case it was sufficient to provide a list of employees by reference to their rank – this reflected how pilots were listed in the employer's corporate directory. The union had not failed to provide the information required by statute simply because it would have been helpful for the airline to have additional information about the fleet to which pilots were assigned.