Empty platforms and trains are pictured at Waterloo Station in London on June 21, 2022, as the biggest rail strike in over 30 years hits the UK.
Train companies said only a fifth of passenger services would run, as about 40,000 cleaners, signalers, maintenance workers and station staff walked off the job in Britain's biggest and most disruptive railway strike for 30 years.
The same workers held 24-hour strikes on Tuesday and Thursday in a dispute over jobs, pay and working conditions.
The Rail, Maritime and Transport Union is seeking a substantial pay raise as workers face a cost-of-living squeeze amid four decade-high inflation rates. Train companies, meanwhile, are seeking to cut costs and staffing after two years in which emergency government funding kept them afloat during the pandemic.
Union General Secretary Mick Lynch said rail workers would not accept ``being thrown on the scrapheap after being praised as heroes during COVID,'' and warned there could be more strikes over the summer.
``We won't hesitate to use more industrial action if we can't reach an agreement or if the companies carry though their threats to make people redundant,'' he told Sky News.
The Conservative government insists it will not get involved in the dispute pitting the union against 13 privately owned train-operating companies and the government-owned National Rail infrastructure firm.
But the union accuses the government of scuttling negotiations by preventing employers from improving on the 3% pay raise on the table so far. Britain's inflation rate hit 9.1% in May, as Russia's war in Ukraine squeezes supplies of energy and food staples while post-pandemic consumer demand soars.
Prime Minister Boris Johnson said rail passenger numbers had only returned to 75% of pre-pandemic levels and there needed to be ``reform and improvement in the way the railways work, and modernization.''
He has also warned that big pay raises would spark a wage-price spiral driving inflation even higher.
Unions have told the country to brace for more as workers face the worst cost-of-living squeeze in more than a generation. British Airways workers at Heathrow Airport voted to strike over the summer vacation season, lawyers are planning a walkout starting next week, and unions representing teachers and postal workers plan to consult their members about possible action.
Britain, like much of Europe, is suffering from rocketing inflation and stagnant economic growth, raising the prospect of a summer of strikes across the continent.
Mainland transport strikes
Staff from budget Irish airline Ryanair staged strikes in Spain, Italy, France, Portugal and Belgium on Saturday, forcing the cancellation of two flights between Lisbon and Brussels.
Ryanair staff staged their second day of action in Spain, resulting in delays to flights but so far no cancellations.
One of the unions calling the strike said that, as of 10:00 am (0800 GMT), "there have been 15 delayed flights, both arrivals and departures.
"It is expected that this situation will increase throughout the day and tomorrow, as Ryanair's maximum profit system of leaving the minimum time between flights will cause delays," it added.
The aviation sector is struggling to recover from the pandemic, which led to mass layoffs as international travel was put on hold.
Faced with staff shortages, Amsterdam's Schiphol Airport was forced to announce earlier this month that it would be limiting traveller numbers this summer and cancelling flights.
The shortages have already caused hundreds of flights to be cancelled, while huge queues have angered travellers.