Facility time
A. It’s very unlikely that you’re entitled to payment for this work. Employees who are union reps of an independent and recognised trade union are entitled to reasonable time off during working hours to carry out certain trade union duties (Section 168, Trade Union and Labour Relations Act).
The relevant Code of Practice (CoP), the Acas Code of practice on time off for trade union duties and activities, confirms that reasonable time off may be sought to prepare for collective bargaining negotiations. So this is the type of work you could claim reasonable time off for.
In terms of what would be considered reasonable time off, this is a question of fact, taking into account things like how much time off is requested, why and how often. There is a lot of guidance on this in the CoP.
The problem is that you’re not carrying out this work in normal working hours. You’re only legally entitled to be paid for union work carried out during normal working hours (Hairsine v Kingston Upon Hull City Council).
Your best option is to make a request to your employer to take paid time off during your working day.
www.acas.org.uk/media/pdf/n/k/Acas_Code_of_Practice_Part-3-accessible-version-July-2011.pdf