Provided your union is independent and recognised by your employer you are entitled to reasonable time off, with pay, for union duties. There is an ACAS Code of Practice containing some examples; (negotiating meetings, some forms of training). You can view the code in pdf format on the ACAS site.
Reasonable time off for union members, as distinct from officials, is also available, without pay, for union activities, but your employer does not have to pay for this time off. Such time off may include attending union information meetings.
