Britain is facing a wave of rail strikes in the run up to Christmas and into the new year as workers escalate a protest over pay and proposed reforms to the network.

The National Union of Rail, Maritime and Transport Workers said Tuesday that over 40,000 of its members would walk out on Dec. 13, 14, 16 and 17 as well as Jan. 3, 4, 6 and 7.

The strikes will affect Network Rail and 14 train companies across the UK, and come alongside an overtime ban, from Dec. 18 until Jan. 2, meaning workers will refuse extra shifts during the holiday period.

The work-to-rule action threatens widespread train cancellations as people visit relatives for the festive period.

Workers in a number of sectors, including postal deliveries and health services, are demanding pay rises that keep pace with inflation, which rose to 11.1% in the UK last month. Rail staff are also unhappy about plans to change working patterns in light of changing demand following the Covid-19 pandemic.

The strikes will cause “huge damage” to the hospitality and retail sectors as they enter the crucial Christmas period, according to a spokesperson for the Rail Delivery Group, which represents train companies.

However, they added that they “can see the outline of a credible deal” following positive talks.