Strikes by train drivers in Britain could continue for three more years, a trade union boss has warned.
Aslef general secretary Mick Whelan spoke as the majority of Britain's train services were cancelled on Friday due to industrial action.
Train driver members of Aslef and the Rail, Maritime and Transport union (RMT) walked out in a long-running dispute over pay and conditions.
This has left large parts of the country with no services all day, as operators such as Avanti West Coast, CrossCountry, Northern and Southern are not running any trains.
Whelan told the PA news agency that train drivers have not had a pay rise in four years.
He said: "What option do we have?
"If you haven't had a pay rise for four years, do you wait five? Do you wait six or seven?"
Whelan said Aslef members "don't want to go back until we get a resolution."
Negotiations with the Rail Delivery Group (RDG) – representing train operators – have "gone backwards," according to Whelan.
He added: "Maybe they'll come with a different attitude next week. We don't know yet."
RDG chairman Steve Montgomery said negotiations with Aslef are "going backwards" and "the talks have not moved on as quickly as we'd like."
He told Sky News: "We all understand that we want to give our staff a pay increase, [it's] naturally important, particularly in these economic climates.
"But drivers' average wages are £60,000 [$73,500] at this moment. We are offering up to £65,000 over two years. That's quite a significant increase for people."
Aslef says the offer would add a "significant" number of contracted hours to drivers.
Montgomery said "we feel closer to a deal" with the RMT.
He went on: "RMT are presently consulting their members [on an offer] at this moment in time.
"What we are seeking from RMT is to put that offer out to a referendum to the members and let them decide whether this offer is acceptable as a best and final [one].
"I'm hopeful that the offer we've made will stop the strikes."
He apologized to passengers for the "very limited service" on Friday, and said the disruption would last "all day," with some services starting "slightly later" on Saturday.
Train drivers took part in the day of industrial action on Wednesday, which also involved teachers, university staff, civil servants, bus drivers and security guards.
About 1,900 members of Unite working as bus drivers for Abellio in London are completing a three-day strike on Friday in a separate dispute over pay.
