The RMT has reacted to the latest pay offer from the Rail Delivery Group by calling another strike of its Network Rail members.

The stoppage, from 18.00 on Christmas Eve to 05.59 on 27 December, will affect travellers during the late afternoon and evening of Christmas Eve, because there are no National Rail trains on Christmas Day and very few on Boxing Day, but projects at more than 300 worksites over the holiday period are now set to be disrupted.

Network Rail's chief negotiator Tim Shoveller said the union is ‘playing fast and loose with people's Christmas plans and the new strike dates announced deliberately target vital engineering work designed to improve the railway’.

RMT general secretary Mick Lynch said: ‘We remain available for talks in order to resolve these issues but we will not bow to pressure from the employers and the government to the detriment of our members.’

Strikes of 48 hours already called for 13-14 and 16-17 December will go ahead, and these will affect train operators as well as Network Rail.

Transport secretary Mark Harper responded: ‘It’s incredibly disappointing that, despite a new and improved deal offering job security and a fair pay rise, the RMT is not only continuing with upcoming industrial action but has called more strikes over Christmas.

‘It’s especially disappointing given the TSSA union has described this new and improved deal as the “best we can achieve through negotiation” and called off strikes.

‘The government has played its part by facilitating a fair and decent offer but, by instructing its members to reject it, the RMT has failed to play its part and our rail network now faces more harmful disruption rather than helpful discussion.’

The offer which the RMT has rejected consisted of a ‘framework agreement’,which would have funded pay increases of up to 8 per cent for the pay awards in 2022 and 2023. The RDG had said ‘changes to working practices’ were also part of the deal, and unconfirmed reports have claimed that these include many more trains without conductors, when their doors would be operated by the driver. Even recently-built main line trains include door controls in the driver’s cab.

Meanwhile, the RMT is putting a new offer from Network Rail to its members in an electronic referendum, accompanied by a recommendation to reject. This ballot will close on 12 December at midday.