More than 830,000 people have signed an online petition launched by Uber, urging Tf L to reverse its ruling.
Mick Whelan, general secretary of Aslef, said: ‘We have been talking to the company over the last fortnight in parallel, but separate, talks about drivers’ terms and conditions, industrial relations and pay.
Many of their key seats were along Southern routes serving Croydon, Eastbourne and Brighton.
Home Secretary Amber Rudd also came close to defeat in Hastings.
The introduction of more driver-only trains would give responsibility to drivers instead of guards to open and close the train doors. But the Rail Delivery Group, which represents train operators, said more than half of trains in Britain, including the London Underground, operate with drivers in charge of closing the doors.
It argues that the change would reduce the time that trains have to wait at stations.The pay rise has been given the green light by Southern’s parent company Govia Thameslink Railway (GTR).