If you are called for jury service it is treated as authorised leave of absence for pension purposes.
If you are paid you will pay pension contributions on the pay you receive and build up your pension normally.
If you are unpaid you can pay Additional Pension Contributions (APCs) for the lost pension. The cost of paying for lost pension is in accordance with guidance from the Government Actuary Department (GAD).
When you return from jury service your employer will write to you to ask if you want to pay APCs for lost pension. They will let you know the relevant timescales.
If you decide to pay APCs within 30 days the cost is shared between you and your employer. You pay one third and your employer pays two thirds of the cost. You can decide to pay after 30 days but you will pay the full cost. There are deadlines restricting your decision and your employer will let you know this in the letter to you.