The Government has been accused of spending millions of pounds of taxpayers' money "bailing out" troubled private train firm Southern "for ideological reasons", after pledging a further £20m to improve its poor performance.

Southern cost taxpayers some £40m of public funding as part of its franchise deal last year, and officials said the newly announced money would be spent upgrading infrastructure used by the company’s trains.

Exasperated passengers have suffered hundreds of cancelled and delayed services on Southern, only to be told they would face higher ticket prices for their journeys in January.

Ministers have resisted demands to take the franchise into public ownership and instead announced the new funding alongside a taskforce to review services and drive improvements.

Transport Secretary Chris Grayling said: “I want the Southern network to be run by a team of people who work together to make sure passengers get decent journeys and that problems are dealt with quickly. This review will suggest how we achieve a joined-up approach to running the train and tracks and make things work better for the public.

“We also need to get to grips with things that go wrong on this part of the network. That is why we are putting in place a £20m scheme to tackle the cause of breakdowns that too often cause frustrating and damaging delays on the network.” Mr Grayling said the former Virgin Trains chief operating officer Chris Gibb would head a new “project board” to achieve fast improvements.

The £20m will go to placing more rapid response teams on the franchise, accelerating the replacement of worn track and hiring extra staff at key stations to make sure trains depart on time. Officials said there would also be £3.5m on removing vegetation from tracks and £4.9m for improvements at depots used by Southern.

Southern rail strikes: On board the 5.20pm from Victoria

The franchise, run by Govia Thameslink Railway, was hit by a series of delays and cancellations for weeks due to a shortage of staff and strikes in a row over the role of conductors. The company blamed high levels of staff sickness for the travel chaos suffered by passengers and eventually announced an emergency timetable which saw a further 350 services cancelled over the summer.

Data released earlier in 2016 showed GTR had the worst punctuality in the country over the past year with just 81.5 per cent of trains on time. At the same time David Brown, the chief executive of Go Ahead, which operates three franchises including Southern through GTR, saw his pay deal jump to £2.16m last year from £1.96m the year before.

Andy McDonald, shadow Transport Secretary, said: "As we have seen with the Southern Rail debacle, ministers are clinging to a failed model for purely ideological reasons and commuters are being made to pay the price. This is why Labour is committed to bringing rail franchises back under public ownership as they expire.”

Liberal Democrat transport spokesperson Jenny Randerson branded the money a "bailout" that is being left "in the hands of a failing franchise".

The RMT transport union general secretary Mick Cash said: “This stinks of another multimillion pound taxpayer subsidy to bail out the failing Southern rail part of the Govia Thameslink franchise. If there’s money to prop up this private outfit, why isn’t there cash available to make sure that the guards and safety are protected on their trains?

“If this huge chunk of money was allocated to maintaining the safety-critical role and the jobs of the train guards on the Southern services, we could have avoided the strike action that has been forced on us again next week by the penny-pinching and intransigence of GTR.”

Southern said this week that 119 train services will be restored to the timetable from next Monday, following cancellation over the summer. However, further strikes are expected next week.

GTR chief executive Charles Horton said: “We welcome the benefits this £20m improvement package will bring for passengers, tackling some of the key infrastructure challenges on the network.