The head of Govia Thameslink Railway is set to resign following months of controversy over delays and cancellations to services.

In a letter to staff, Charles Horton said the company had been going through some "very challenging" times in recent weeks and it was "the right time to hand leadership of GTR to a new pair of hands".

Some 13 per cent of GTR trains were either cancelled or significantly delayed in the first two weeks after new timetables were introduced on May 20.

Thameslink and Great Northern services were particularly hit, with some passengers left stranded on platforms for several hours.

Mr Horton said: "In my view, this was an industry-wide failure of the timetabling process. But with leadership comes responsibility and so I feel it is only right that I step down.

"Before my departure in a few weeks' time, I will continue to work with my colleagues to ensure a smooth handover as we work to put our railway back on track and give our passengers a reliable service once again."

Mr Horton will remain in post for a "short period" to oversee the development of a temporary timetable, a spokesman for GTR's parent company, Go-Ahead, said.

Industry sources stressed that Mr Horton is not taking sole responsibility for the disruption, with Network Rail also blamed for delays in approving timetables.

A Department for Transport spokesman said: "Clearly the disruption that passengers have experienced following the recent timetabling changes has been unacceptable and it is right that the industry takes responsibility for its performance."

The DfT is being investigated by the Office of Rail and Road (ORR) in relation to the chaos.

The rail regulator is analysing the department's role in "managing risks around major network changes", as well as the actions of train operators and Network Rail.

A spokesman for Go-Ahead said the firm would not comment on Mr Horton's remuneration following his resignation.

It emerged on Friday that Network Rail's chief executive Mark Carne and chief finance officer Jeremy Westlake will not take their annual bonus for the last financial year due to the disruption.

Mr Carne, who was awarded a CBE in last week's Queen's Birthday Honours, is leaving Network Rail later this year.