The postal strikes are estimated to have cost UK businesses £1.04bn in additional costs and lost sales, with online businesses particularly hard hit.

Online retailers are estimated to have lost £156m due to the strikes, according to data from Kelkoo, the comparison shopping site, and the Centre for Economics and Business Research. This includes £85m in extra costs for deliveries and £71m in lost sales or refunds as a result of items being undelivered.