Gavin Williamson sacking: How the Huawei leak hunt led to defence secretary's phone

Williamson thought to have been first cabinet minister interviewed in probe into National Security Council breach

Shortly after a top-secret meeting to decide if Huawei should be allowed access to Britain's telecoms network, Gavin Williamson spoke to the journalist who revealed the details of the government's discussion, The Independent understands.

However, the now former defence secretary repeatedly denied he had been source of the information when he was interviewed by Cabinet Office officials during an inquiry into the unprecedented leak of information from the National Security Council, which receives intelligence from international security agencies.

The Independent understands the phone interview with Mr Williamson took place on Friday, after he interrupted a holiday in Scotland to cooperate with the investigation. It is believed he was the first cabinet minister spoken to during the probe ordered by Sir Mark Sedwill, the cabinet secretary and national security adviser.

He was one of at least five cabinet ministers at the security council meeting who opposed allowing Huawei into the UK’s 5G network, something the US and other allies consider to be an intelligence risk because of the firm’s alleged ties with the Chinese state.

With Mr Williamson’s insistence that he was not responsible for the leak, the focus has also been on his staff and advisers. Some of them, The Independent has learned, have already been interviewed and some have had their security clearances withdrawn.

Sources close to Mr Williamson are claiming his sacking has been orchestrated by Sir Mark Sedwill. The pair have not seen eye to eye on a number of issues and the former defence secretary had been critical of a defence security review which had been undertaken by the cabinet secretary.

Some of Mr Williamson’s staff were in a bullish mood after their boss’s departure, saying that they have information which points the finger of guilt about the leak being at others who had attended the meeting.

Sources in the Cabinet Office, however, say they are satisfied that the source of the leak has been identified. In her letter to Mr Williamson, the prime minister wrote “no other credible version of events to explain this leak has been identified”. Theresa May claimed that her defence secretary had not been as candid with the investigators as others.

She wrote: “They have all answered questions, engaged properly, provided as much information as possible to assist with the investigation and encouraged others to do the same. Your conduct has not been of the same standard as others.”