Jeremy Corbyn has had a “full exchange of views” with the head of the civil service over reports that senior officials claimed he would not be physically or mentally up to the job of Prime Minister.

Labour said that during a 45-minute meeting with the party leader in his Commons office, Sir Mark Sedwill, the Cabinet Secretary, accepted there had been “evident malicious intent” behind the civil service breach of neutrality.

On Tuesday, Jon Trickett, the Shadow Cabinet Office Minister, who was at the meeting, stressed the need for a “thorough investigation, independent of the Cabinet Office”.

Sir Mark made clear there would be an “independent element” to the inquiry; that Mr Corbyn and Mr Trickett would receive regular updates and the investigation would report its findings as soon as possible.

A Labour Party spokesman said: "The meeting was frank and detailed, with a full exchange of views.

"The seriousness of the civil service breach and the evident malicious intent behind it was acknowledged by all participants in the meeting.

"Jeremy Corbyn and Jon Trickett pressed the case for a fully independent investigation to restore trust and confidence in the civil service.

"They were promised an independent element to the civil service investigation, that they will receive regular updates on its progress and that it would report as soon as possible.

"They made clear the credibility of the investigation will be assessed on the basis of its results," he added.

Earlier, Mr Corbyn's spokesman said the actions by two unnamed officials at the "apex of the civil service" were "out of order".

The row was triggered by a weekend report in The Times, which said the future of the 70-year-old Labour leader was openly discussed at an event attended by Whitehall mandarins amid suggestions he had become "too frail and is losing his memory".

One senior official was quoted as saying: "There must be senior people in the party who know that he is not functioning on all cylinders," while another said: "There is a real worry that the Labour leader isn't up to the job physically or mentally but is being propped up by those around him."

Mr Corbyn's spokesman said what happened was "entirely unacceptable" and "unprecedented in recent times".

It was, he stressed, also based on false information because Mr Corbyn was in "excellent" health.

"So, on both counts you are talking about a very serious breach of civil service neutrality; a principle that absolutely underlines our democratic constitution."

The spokesman said it was not appropriate for the civil service "to be marking their own homework" and that a “genuinely independent investigation” should take place, noting how there had to be an "independent element in the investigation to restore confidence in those people at the apex of the civil service".

He added: "Clearly, there is resistance and anxiety in sections of the Establishment about the election of a radical, transformative Labour government that is determined to redistribute wealth and power. That clearly is the context in which this is taking place."