Drivers on the London Underground are threatening to walk out on April 29, which is the date of the royal wedding, when Prince William and Kate Middleton are due to wed. Drivers last went on strike on Boxing Day, and the dispute over bank holiday pay remains unresolved. Management took legal action to halt the Boxing Day walkout but it failed and the strike went ahead, causing disruption on one of the busiest shopping days of the year. Unions demand triple pay and a day off in lieu for working on bank holidays.