ANDY Burnham is calling for a official investigation to be launched into Northern Rail after weeks of disruption for travellers.

The Mayor of Greater Manchester has written to Transport for the North (TfN) highlighting a series of missed deadlines and examples of serial poor performance, including frequent delays, last-minute cancellations and often dangerously overcrowded on-board conditions.

In questioning whether Northern's recent record has resulted in the operator breaching the terms of its franchise, Mr Burnham highlighted 'an unacceptably poor service in recent weeks'.

He said: "Enough is enough. Northern Rail passengers, the people of Greater Manchester, deserve so much better than the dire service they have been forced to endure in recent months.

"I am calling for TfN formally to assess whether Northern is in breach of its franchise agreement."

In his letter to John Cridland, chairman of TfN, the Mayor sets out the causes of his frustrations and calls for action.

"I believe Transport for the North should now consider escalating its response and assess whether Northern are in breach of the performance targets as set out in its franchise agreement.

"I would also be grateful if you could set out what actions can be taken by Transport for the North should it be determined that Northern are in breach."

It comes after the Mayor wrote to Northern in November calling the situation 'completely unacceptable'.

In further correspondence with Northern, Network Rail and the Secretary of State for Transport last month, Mr Burnham called for immediate action to be taken to improve services.

"The time has come to increase pressure on Northern to start delivering for its customers," added the former Leigh MP.

RMT has welcomed the Mayor's calls for an inquiry into Northern Rail.

Mick Cash, RMT general secretary, said: "RMT welcomes the fact that the Mayor of Manchester is supporting our call for an inquiry into the crisis in Northern Rail services.

"It is clear however that the Northern franchise is in total meltdown and these problems are being caused by the company putting profits before passengers.

"What is even more galling is that because Northern is owned by German state railways it is their domestic operations that are benefitting off the backs of the misery experienced by Northern Rail passengers.

"If the German state can own Northern railways so can the British state and it is now time to strip ARN of the franchise and return it to public ownership as soon as possible."

Northern rail have been contacted.