Train drivers at London Underground and 16 rail companies have announced a wave of industrial action that could cause chaos for passengers across the UK and bring the entire tube network in the capital to a halt on certain days. Tube drivers are to stage two one-day strikes in April and May unless a dispute over changes to working conditions is resolved in time. The members of the Aslef union, which represents 96% of train drivers in Britain, plan to strike on Monday 8 April and Saturday 4 May. The strikes would start at 12.01am and finish at 11.59pm. Meanwhile, other Aslef members will embark on a wave of one-day strikes and a six-day overtime ban next month in a dispute over pay. Drivers had not had a pay rise for five years, since April 2019, the union said. Train drivers will strike at Avanti West Coast, East Midlands Railway, West Midlands Trains, and CrossCountry on Friday 5 April; at Chiltern, GWR, LNER, Northern, and TransPennine on Saturday 6 April; and at c2c, Greater Anglia, GTR’s Great Northern, Thameslink and Southern/Gatwick Express, Southeastern, South Western Railway mainline and depot drivers, and SWR Island Line on Monday 8 April. Members will also refuse to work their rest days – non-contractual overtime – from Thursday 4 to Saturday 6 April and from Monday 8 to Tuesday 9 April. Aslef’s general secretary, Mick Whelan, said: “Our members voted overwhelmingly – yet again – for strike action. Those votes show – yet again – a clear rejection by train drivers of the ridiculous offer put to us in April last year by [the train operators’ body] the Rail Delivery Group which knew that offer would be rejected because a land grab for all the terms and conditions we have negotiated over the years would never be accepted by our members. “We have given the government every opportunity to come to the table but it is now clear they do not want to resolve this dispute. They are happy for it go on and on.” The union has called 14 one-day strikes during this 20-month dispute. A Rail Delivery Group spokesperson said: “We want to resolve this dispute, but the Aslef leadership need to recognise that hard-pressed taxpayers are continuing to contribute an extra £54m a week just to keep services running post-Covid. We … remain open to talks to find a solution to this dispute.” Finn Brennan, Aslef’s full-time organiser on London Underground, said: “Aslef tube train drivers will strike in April and May in a long-running dispute over London Underground’s failure to give assurances that changes to our members’ terms and conditions will not be imposed without agreement and that all existing agreements will be honoured.” He said under the proposals, staff would have to work longer shifts, spending up to 25% more time in the cab, and current working agreements would be removed in the name of “flexibility and efficiency”. Brennan said management had also failed to deliver on commitments made to the union on making drivers’ cabs secure, on police numbers on the night tube, and on training. He said the union remained ready to talk but wanted to see “real action from management, not easily broken promises”. The two sides are not currently in negotiations. A TfL spokesperson said: “We have been in long-term discussions with our trade union colleagues on how to modernise procedures and processes on London Underground. We have no plans to impose these changes and have committed to no one losing their job as part of these changes … We urge Aslef to continue discussions with us so that disruption for Londoners can be averted.” A Department for Transport spokesperson said: “Aslef is the only rail union continuing to strike … Having resolved disputes with all other rail unions, the transport secretary and rail minister have ensured that a pay offer is on the table – taking train drivers’ average salaries from £60,000 up to £65,000.”