Britain remains in the grip of industrial unrest as Southern Railway train drivers and British Airways cabin crew continue to support strikes, causing fresh disruption.
Southern's 300,000 passengers were worst affected, with virtually none of the 2,200 daily services running because of a 48-hour walkout by members of Aslef in a bitter dispute over driver-only trains.
Southern ran a handful of trains from Brighton to London on Tuesday morning, driven by driver/managers, and planned to operate eight driver-only trains in each direction in the morning and evening peak hours between Caterham and the capital.
Buses and coaches were laid on but hundreds of thousands of people could not get to work again, following months of disruption because of industrial action, staff shortages and other problems.
Mick Whelan, general secretary of Aslef, said: "We greatly regret the industrial action. We don't want to inconvenience passengers, nor do our members want to lose money, because we want to help build a better railway for Britain.
"But we have been forced to go on strike by an intransigent management that has not been prepared to negotiate with us.
"Southern are bullies. Throughout this dispute, from when they first announced their intentions 10 months ago, they have tried to force through changes in the terms and conditions of staff by tearing up agreements rather than by negotiating.
"In contrast, we stick to deals we have made and have always been willing to negotiate when someone shows goodwill. That is how we managed to strike a deal last year with ScotRail which works well for the company, the passengers and the staff."
Transport Secretary Chris Grayling repeated his view that there were no grounds for the strike, saying: "I am deeply disappointed and frustrated that the union has insisted on this damaging and disruptive strike action, which will cause misery for thousands of people."
Southern drivers were striking on Tuesday, Wednesday and Friday, as well as for three days later in the month.
Members of the Unite union at BA have launched a 48-hour strike in a row over pay, leading to a number of flights to and from Heathrow being merged.
The dispute involves so-called mixed fleet cabin crew who joined BA since 2010 and who Unite claims are on "poverty pay".
Unite national officer Oliver Richardson said: "Going on strike is never an easy decision, so we are pleased with the numbers of mixed fleet cabin crew who have taken the courageous step to take a stand against poverty pay at British Airways.
"This is a low-paid workforce struggling to make ends meet on wages which are among the lowest in the airline industry.
"It is to the shame of British Airways, a company which prides itself as a premium brand, that members of its loyal workforce are forced to take second jobs to make ends meet or turn up to work unfit to fly because they can't afford to take the day off sick."
BA said 22 flights to and from Heathrow Airport would be cancelled on Tuesday because of the strike, out of 800 in total, with a similar number on Wednesday.
Meanwhile, London Underground services returned to normal after a strike by station staff crippled the Tube on Monday.
Transport for London urged the Rail, Maritime and Transport (RMT) union and the Transport Salaried Staffs' Association (TSSA) to continue discussions to resolve the Tube dispute, which centres around job cuts and ticket office closures.
TSSA general secretary Manuel Cortes said: "We hope London Underground will resume talks with us without delay so that a resolution to this long-standing dispute can be found."
RMT leader Mick Cash said: "RMT's executive will be considering the next steps and the union remains available for serious and genuine talks.
"However, the union has made it clear that the company need to move away from the piecemeal and incremental approach to putting jobs back into the system."
Unite members will hand in a letter to Marks and Spencer's head office on Wednesday calling on the retailer to support its campaign.
The union said the second day of the strike coincides with a roll-out of a new M&S food range on short-haul flights across British Airways.
Unite national officer Oliver Richardson said: "Cabin crew working for British Airways' 'mixed fleet', 36,000 feet up in the air, face earning up to £6,000 less basic pay than M&S staff selling the same food in store."
A BA spokesman said: "New cabin crew in their first year working full-time at British Airways receive more than £21,000 based on pay, allowances, incentive and bonus."