LONDON -- Efforts to avert a two-day rail strike in southern England collapsed Sunday when union leaders and the management of South West Trains failed to resolve a dispute over pay and the disciplining of union officials, according to a wire service.

The strike will halt trains across southern England and into London's Waterloo Station starting early Monday, and on Tuesday. A similar strike Thursday and Friday halted 90 percent of South West trains.

In a separate rail strike, ScotRail will cancel a quarter of its services on Monday because of a pay dispute involving train drivers on the railway, which operates within Scotland and to London and other major British cities.

After six hours of negotiations between South West Trains and leaders of the Rail, Maritime and Transport Union, the rail company said, “We are desperately sorry for our customers that our efforts have failed to avert a strike.”

Vernon Hince, the union's acting general secretary, accused the company of prolonging the dispute by making a pay offer of less value than that tabled previously.

“It is preposterous to believe that a lower offer would be acceptable to my members. ... The blame for these two strikes falls squarely at the management's door.”

But the company insisted its pay offer of 7.6 percent over 18 months had met in full the union's pay claim.

The company said the main issue was disciplinary action taken against Greg Tucker, a union official who was downgraded last year from a train driver to a ticket collector.

Hince, however, denied that the dispute was now about Tucker and said there were two disputes -- one relating to pay, and the other about the absence of disciplinary procedures, which “affects several of our representatives.”

The rail company said it would provide buses Monday to replace many trains. Some train services are expected to run despite the strike. but most of the usual 1,700 daily services will be canceled or disrupted by the strike.