London-Hundred thousands of rail passengers in London and south England suffered on Monday with the start of a strike that will continue for the coming four days.

Southern Rail workers walked off the job Monday over plans to remove conductors from trains.

Southern, which runs trains between London and its densely populated southern commuter belt, has seen months of one-day strikes and cancelations that it blamed on staff shortages.

Southern estimates that around 60 percent of its scheduled trains will run as usual during the strike, which is considered to be the longest on British railways since 1968, with eight routes closed altogether and several others running a limited service.

Queuing systems could be in operation to prevent dangerously overcrowded platforms.

The prime minister “strongly condemns” a five-day strike that has hit hundreds of thousands of Southern passengers, Downing Street has said.

A spokesman for Theresa May said the action was “only going to cause more disruption and misery.”

Southern’s parent company Govia Thameslink (GTR) says that the change will reduce cancelations since services will no more need drivers and conductors.