Members of the Rail, Maritime and Transport (RMT) union will stage a fresh 24-hour strike on the day of the Grand National in bitter disputes over staffing and the role of conductors.

RMT union members at Southern, Merseyrail and Arriva Trains North will walk out on Saturday, April 8, causing fresh travel misery for hundreds of thousands of passengers.

Many people travel to the Grand National at Aintree in Liverpool by train, so any disruption to Merseyrail services will hit those going to the biggest race in the world.

A strengthened train service often runs on Aintree Race days and a special timetable is put in place for the annual three-day Grand National festival.

The strike on Southern, owned by Govia Thameslink Railway, had been planned for April 4 but was moved to April 8 after the company offered fresh talks if the industrial action was suspended.

RMT members at the three companies staged a 24-hour strike last week, causing most disruption at Merseyrail after drivers refused to cross picket lines.

Talks between the company and the union broke down on Monday, with little sign of any progress in a row over plans to introduce new, driver-only trains, in 2020.

RMT general secretary Mick Cash accused Merseyrail of taking a "cynical and hostile stance".

He said: "RMT recognises the severe impact that the action will have on Grand National Day but we are dealing with an employer that refuses to listen or engage with the union on the critical issue of safe rail operation and we ask the public to understand that we have no option but to take this high-profile action to force the company back to the negotiating table.

"Merseyrail are completely ignoring the clear wishes of their own passengers, who overwhelmingly oppose the idea of driver-only operated (DOO) trains on their network.

"That pig-headed attitude has forced the union's hand and the idea that we would compromise on the fundamental issue of rail safety is absurd."

The Arriva dispute is over similar plans for driver-only operated new trains, with Mr Cash Jan Chaudhry-van der Velde, Merseyrail's managing director, said the RMT had "sunk to a new low" by striking during British horse racing's top event.

He said: "Damaging the company and its passengers is one thing, but damaging the whole of the Liverpool city region on one of its proudest and most important days of the year is impossible to understand.

"The Saturday of the Grand National is one of our busiest times of the year, and we will make every attempt to ensure that we successfully move around the high volumes of people who choose to travel with us that day."

Richard Allan, deputy managing director of Arriva Rail North, added: "We are surprised that RMT has announced strike action for April 8 as we had been in contact with their officials in the last 24 hours to organise further talks.

"We have been clear that we want RMT, along with our people, our customers and stakeholders, to play a role in bringing our modernisation plans to life."

David Sidebottom, director of watchdog Transport Focus, said: "Yet more strikes are being dumped on passengers who may have to cancel plans or endure miserable journeys.

"It is vital that all parties in this dispute get back around the table to resolve this matter without bringing the railway to a standstill."

A Southern spokesman said the firm had yet to receive confirmation of the change to the strike date from the RMT.