Why won't rail bosses take responsibility for timetable chaos?

The boss of Govia Thameslink has apologised for the travel chaos that has afflicted rail passengers, but said he will not resign as the situation is not his fault.

Charles Horton's unwillingness to take responsibility will do little to soothe the anger of commuters, instead it appears to be the latest incident of buck-passing by those in authority over the mess.

In the midst of a third week of disruption on rail services over the new timetables, it remains unclear who is to blame.

• Why won't he take the blame?

Mr Horton insists that the disruption is not that fault of Govia Thameslink Railway, which consists of Southern, Thameslink, Great Northern and Gatwick Express.

He told ITV News the delays were the result of earlier delays to national timetable changes that had been passed on to his company.

"The planning that we would normally do over several months to introduce a major timetable change had to be squeezed into just a couple of weeks," he said.

But asked who should be blamed for the disruption, he said only that the matter would be looked at as part of an official inquiry.

• Who else has faced calls to go?

Earlier this week Chris Grayling, the transport minister, rebuffed calls to step down over the situation. Instead he has promised an inquiry.

Speaking in the House of Commons he said that Govia Thameslink had assured him they were ready to implement the timetable changes.

Peter Hendy, the Network Rail chairman, has also faced calls to go.

In an interview with ITV News he said he should "maybe" resign, but that the "important thing for the moment" was to work to fix the problems.

• So what are the delays being blamed on?

The introduction of new timetables is seen as the reason for the disruption but it appears harder to tie things down beyond that.

Reporting from Westminster, ITV News correspondent Angus Walker said: "Behind the scenes there is certainly a lot of finger pointing going on.

"It's perhaps ironic, laughable perhaps, that the delays are being blamed on the delay of the national timetable changes being delivered to the companies themselves.

"But with so many organisations, so many companies involved, it's very difficult to unpick this mess."

• When will we know who is responsible?

A number of inquiries are planned, which are intended to uncover who is to blame.

Mr Grayling's promised inquiry is due to report at the end of the year, but as yet there is no fixed date for it to deliver its findings.

An inquiry by the Transport Select Committee has also been announced.

Prime Minister Theresa May, meanwhile, has described the disruption to rail journeys as "absolutely unacceptable".