Rail passengers will be able to claim compensation when trains are more than 15 minutes late, under new plans revealed by the Government.
The policy will first be launched on Southern trains, before being rolled out on other Govia Thameslink Railway (GTR) services and across the country.
Existing rules mean passengers can only claim pay outs when services are delayed by at least 30 minutes.
Only three in four GTR trains arrived on time between August 21 and September 17 this year, according to Network Rail.
The Department for Transport could not give a start date for the scheme but said it would apply to Southern services “soon”.
Under the new scheme, the compensation thresholds will be 25% of the single fare for delays of 15-29 minutes, 50% for 30-59 minutes, 100% for 60-119 minutes, and 100% of the total ticket cost - including returns - for delays of two hours or more.
Transport Secretary Chris Grayling said: “We recognise that, above all else, passengers want a reliable train service, but when things do go wrong it is vital that they are compensated fairly.
GTR runs four services, including Southern, Thameslink, Great Northern and Gatwick Express.
But rail union leaders have attacked the announcement as a “gimmick” to divert attention from the chaos on Southern Railway.
Mick Cash, leader of the Rail, Maritime and Transport union, said: “This botched and complicated scheme will come as no comfort to the millions of passengers whose daily journeys are wrecked through the profiteering and under-investment on Britain’s rammed out, privatised railways.
“This scheme will not dent the fat cat profits of the private rail operators who still see the British people as nothing other than self-loading freight there to be fleeced at every opportunity.”