Avanti West Coast train managers are to stage strikes from the end of December until May next year, after 83 per cent of those voting in an RMT referendum rejected the operator’s latest offer.

Strikes which had previously been called for 22, 23 and 29 December had been suspended while the ballot was held.

The dispute is over rest day working.

The union, which had argued that the current arrangements are ‘unacceptable’, said Avanti’s latest offer had included better pay for working rest days and ‘more organised allocation’ of rest day shifts.

Staff are now set to walk out on New Year’s Eve and on 2 January, and also on every Sunday from 12 January to 25 May.

The RMT said ‘sustained’ action was now ‘the only way to focus management’s minds on reaching a negotiated settlement’.

Avanti, which is owned by FirstGroup and Trenitalia, responded that its latest offer had been ‘very reasonable’, and that it was disappointed that new walkouts had been called, because they would cause ‘significant disruption’ over an ‘extended period’.

It added that it was continuing to work with the RMT to resolve the dispute, and that strike day timetables were being prepared.