Members of the Aslef union have rejected a deal aimed at ending a long-running dispute about driver-only trains on Southern Railway.

It is the second time the drivers have gone against a recommendation from their leaders, and deals a huge blow to hopes of a breakthrough in the bitter row.

The vote was 48.2 per cent in favour of the proposed agreement, with 51.8 per cent against, on a turnout of 75 per cent.

Aslef general secretary Mick Whelan said: 'We understand and support the decision arrived at in a democratic vote by our drivers and will now seek new talks with the company and work to deliver a resolution to this dispute in line with the expectations of our members."

Andy Bindon, of Govia Thameslink Railway, Southern's parent company, said: "It's a hugely disappointing outcome for our passengers, particularly as the agreement carried the full support and recommendation of the Aslef leadership.

"We have shown a willingness and desire to find a solution to their dispute and we will now, once again, sit down with the union, understand the issues which led to this regrettable decision by the drivers and try and find a way forward to resolving it."

Passengers have suffered almost a year of disruption on some of the busiest routes in the country because of industrial action and other issues such as staff shortages.

Aslef leaders had recommended that the deal should be accepted, believing it is the best that can be achieved.

The Rail, Maritime and Transport (RMT) union is staging its 31st day of strike action against Southern on April 8, although the two sides are due to have talks this week.

Paul Plummer, chief executive of the Rail Delivery Group, which represents train operators and Network Rail, said the Aslef result was "very disappointing", adding: "A stronger railway needs everyone working together to improve services for passengers, employees and businesses across the Southern region and the whole of Britain.

"We would urge Aslef to return to talks and we call on the RMT to call off its planned strikes on Saturday when people will be going to the Grand National - a much-loved iconic British event watched around the world."

RMT general secretary Mick Cash said: "The result reflects the continuing and deep-seated concern amongst drivers and the wider workforce over the extension of DOO (driver-only operation) and the safety impact on passenger services.

"Southern Rail cannot jam their heads in the sand any longer. We are in talks with the company tomorrow and we now expect the fundamental issues at the heart of our guards and drivers' disputes to be taken seriously.

"There's an easy solution to this long-running industrial dispute and Southern Rail need to join with the unions in reaching an agreement that protects passengers and which recognises the safety critical issues our members have been fighting for over the past year."