Union leaders, the rail minister and industry chiefs are scheduled for showdown talks on Thursday after industrial action on the rail network brought the UK to a standstill for the second day in a row.

Only 20% of services were running as about 40,000 RMT members working for Network Rail and 14 train operators went on strike for a second day. A further 48-hour strike is scheduled for Friday.

Rail passengers have been warned that trains will start much later than usual on Thursday, despite it being a non-strike day, with the first trains much busier than usual because of strike disruption.

The industrial action, combined with the snow and freezing temperatures, contributed to a dramatic decline in footfall in cities across the UK as firms recovering from the pandemic desperately try to claw back business over Christmas.

It comes as the high court on Wednesday granted permission for a legal challenge against the government’s decision to allow agency workers to fill in for striking workers. The TUC is coordinating the case brought by 11 trade unions who represent millions of workers, with a hearing set to be held from late March next year.

The TUC said the judicial review against “anti-worker” regulations was a “major blow” against the government’s attempts to undermine workers’ right to strike for better pay and conditions.

About 115,000 members of the Communication Workers Union (CWU) who work for Royal Mail also took part in further industrial action on Wednesday and will also strike on 15, 23, and 24 December, with pictures today showing enormous stacks of letters and packages piled high outside depots.

Up to 100,000 nurses who are members of the Royal College of Nursing (RCN) will also take part in their first ever industrial action on Thursday.

The RMT confirmed that it will hold fresh talks with the rail minister, Huw Merriman, on Thursday , along with the train operating companies and Network Rail.

The union’s general secretary, Mick Lynch, said: “I congratulate RMT members who have shown enormous dignity and rock-solid fortitude throughout this 48-hour strike. They have shown how important their work is to the functioning of the economy and wider society.

“All they want is a negotiated settlement on job security, a decent pay rise and good working conditions.”

Figures from retail analysts Springboard showed the impact of freezing temperatures and strikes on the high street, with footfall on Tuesday – the first day of the rail strikes – 37% lower than on the same day in 2019.

Across the UK it was down by 26%, while footfall at shopping centres was 28% lower and 9% down in retail parks.

The latest data from TomTom indicated that strike action was also affecting the amount of people getting in their car as congestion in the larger cities increased across the board. London recorded an increase of 10%-15%.

Despite the fresh talks between the RMT, rail bosses and the government, hopes are slim that another two-day strike on 16-17 December can be averted.

An overtime ban at the train operator will also cause various degrees of disruption until more strikes on 3-4 and 6-7 January. Another strike will mainly affect engineering works from late Christmas Eve until 7am on 27 December, while ongoing repair works will also affect remaining travel over the festive period.

Further disruption is expected on the railway after Christmas as the smaller TSSA union said 700 members working for West Midlands Trains (WMT) and Great Western Railway (GWR) would strike on Wednesday 28 December in a dispute over pay, jobs and conditions.

Elizabeth line workers, who are employees of Rail for London Infrastructure (RfLI), have also voted overwhelmingly for strike action. Members of the Prospect union rejected a 4% pay offer for 2022 and said the offer was “well below the current inflation rate”.

There were signs of progress in other industrial disputes as the RMT members who work as security guards on Eurostar services called off strikes planned later this week. The workers, employed by contractor Mitie, were due to take industrial action on Friday and Sunday in a dispute over pay.

RMT said it suspended the strikes this week so that security staff could vote in a referendum on the latest offer from Mitie. However, further strike action on 22 and 23 December will take place if the dispute is not resolved, the union said.

Mitie said that pay negotiations with RMT were ongoing and that contingency measures were in place so that Eurostar services would not be affected.

Members of the Unite union who work for Network Rail in electrical control rooms also called off planned industrial action and accepted an improved pay offer.

Andrew Haines, chief executive of Network Rail, said: “The RMT leadership needs to think long and hard about what to do next. Further strike action will cause further misery for the rail industry and for their members, who will lose pay.

“This news is especially frustrating, given that we learned today that colleagues represented by Unite union have accepted the very same offer put to RMT members. The RMT are the outliers here – they need to stop playing politics and work with us to bring this dispute to an end.”