British Prime Minister Boris Johnson on Tuesday called for a sensible compromise on the pay demands by workers' unions that have resulted in the UK's worst rail strike in 30 years, with a majority of the staff walking out to cripple the networks.

Just one in five trains are expected to run on Tuesday, Thursday and Saturday when workers are on strike, with services across England, Wales and Scotland being affected from Monday evening. Passengers have been urged to travel by train only if necessary.

"Too high demands on pay will also make it incredibly difficult to bring to an end the current challenges facing families around the world with rising costs of living," said Johnson, ahead of a Cabinet meeting at Downing Street.

"Now is the time to come to a sensible compromise for the good of the British people and the rail workforce," he said.

Thousands of staff at public-owned Network Rail and 13 rail operators walked out from midnight after last-ditch talks to avoid the strikes failed on Monday. The RMT rail union accused the government of preventing rail network employers from freely negotiating on pay. The union is reportedly asking for a pay rise of 7 per cent, which is lower than inflation but higher than that offered by employers.

"It is clear that the Tory government, after slashing GBP 4 billion of funding from National Rail and Transport for London, has now actively prevented a settlement to this dispute, said RMT union's general secretary Mick Lynch.

The rail companies have now proposed pay rates that are massively under the relevant rates of inflation, coming on top of the pay freezes of the past few years. At the behest of the government, companies are also seeking to implement thousands of job cuts and have failed to give any guarantee against compulsory redundancies," he said.

Network Rail CEO Andrew Haines said the government is not the constraining factor in negotiations", amid reports that the unions had rejected a 3 per cent pay rise offer.

In a separate row involving London's Tube network, London Underground network workers are also on strike on Tuesday over job cuts and change to their pensions.

"We have a responsibility to tackle inflation and stop it becoming entrenched," Downing Street said in a statement.

"To do this we must ensure that pay settlements are sensible and do not scramble to match inflation, and as a result drive up prices as the cost of goods and service increase to incorporate pay rises," the statement added.