Calls are mounting for a criminal probe into allegations that former defence secretary Gavin Williamson broke the Official Secrets Act by leaking details of intelligence discussions over Chinese technology giant Huawei.
Dramatically sacked after the prime minister said she had received “compelling” evidence that he passed on information from a National Security Council meeting, Mr Williamson has strenuously denied he or any of his staff were to blame for the leak.
In a letter to Theresa May, he said he rejected the offer to resign rather than be sacked, saying that this would have implied guilt.
He also insisted he would be “absolutely exonerated” by a police investigation.
Both his supporters and critics have called for a criminal investigation to establish the truth of the allegations.
Is Mr Williamson being investigated?
Currently, he is not being investigated by police.
His sacking came after an internal inquiry carried out by Sir Mark Sedwill – the cabinet secretary and national security adviser.
He stepped in after The Daily Telegraph revealed that a meeting of the top-secret National Security Council (NSC) had agreed to give Huawei a role in building the UK’s 5G network.
Meetings of the NSC are carried out behind closed doors and details are kept secret, so their appearance in a newspaper caused uproar in Westminster.
There were also concerns that such an unprecedented leak could affect Britain's intelligence relationship with key allies.
The US has banned Huawei from its government networks and put pressure on the UK to do the same, over fears – denied by the company – that it is a vehicle for Chinese government spies.
Mr Williamson was among five cabinet ministers reported to have raised objections at the meeting, putting him under suspicion.
All ministers present and their special advisers, have been interrogated in the days since.
Some were ordered to hand in mobile phones to be swept for contacts with The Daily Telegraph.
The prime minister said the probe uncovered “compelling evidence” that Mr Williamson was to blame and had not fully cooperated with the inquiry as others had.
In a letter to Mr Williamson, Theresa May said all others had “answered questions, engaged properly, provided as much information as possible”, adding: “Your conduct has not been of the same standard as others.”
She wrote: “I put to you the latest information from the investigation, which provides compelling evidence suggesting your responsibility for the unauthorised disclosure. No other credible version of events to explain this leak has been identified.”
Is there a criminal probe?
Not yet. London's Metropolitan Police said the alleged leak was “a matter for the National Security Council and the Cabinet Office to look at”.
“At this time, we’re not carrying out an investigation,” a spokesperson added. “Clearly if at any stage we receive any information that would suggest criminal offences have been committed, then we will look into that.”
Metropolitan Police commissioner Cressida Dick said she would reply to letters from politicians calling for an investigation but officers could not progress without seeing the evidence.
“If the Cabinet Office were to send us a referral at any point that related to apparent official secrets or an associated leak, we would assess that, scope it and go through a very formal gateway process for taking on any criminal investigation,” she told journalists.
Ms Dick said the Metropolitan Police had the expertise to investigate Official Secrets Act cases and worked with the Crown Prosecution Service (CPS) on the “complex case law” surrounding them.
When asked if Scotland Yard needed permission to investigate Mr Williamson, Ms Dick said police would “have to be made party to material [held by the government] and at the present time there is no referral and we are not in possession of that material.”
Asked whether Mr Williamson could have broken the law by sharing concerns about a governmental decision that would later be made public, Ms Dick said such questions would be addressed by CPS lawyers.
The fact that the material would include classified intelligence or information subject to the Official Secrets Act makes government sharing unlikely.
There has been no signal from the government that it would support or facilitate a police inquiry.
Asked about the possibility of a prosecution, the prime minister's official spokesman told a Westminster briefing: “It is not for the government to determine prosecutions, but the prime minister has said, from her point of view, that she considers the matter to be closed.”
Can Mr Williamson be prosecuted?
If a criminal investigation took place, prosecutors could consider charging him under offences contained within the Official Secrets Act.
It makes it illegal to disclose covered information or documents “without lawful authority”.
There was a public interest defence until 1989, when the provision was removed from the updated law.
But prosecutors cannot act unless cases are referred to them and the Act stipulates that such a charge would have to be approved by the director of public prosecutions or attorney general.
If an Official Secrets Act case were to go to court, it would trigger complex submissions from intelligence services over redacting evidence and holding hearings in private to protect intelligence.
Juries can only convict someone when their guilt is “beyond reasonable doubt” – a higher legal bar than that used in internal inquiries – and any acquittal would be a scandal for the government.
What is the Official Secrets Act?
The first version of the UK’s Official Secrets Act dates back to 1889, but the law has been updated several time to cover different forms of espionage.
The 1989 act created new laws over the “unlawful disclosure” of information relating to security, intelligence, defence, international relations, crime and investigations.
A briefing paper issued in 2017 by the House of Commons library said prosecutions under the laws have been “very rare” – fewer than one a year.
“For members or former members of the security and intelligence services, any unlawful disclosure relating to security or intelligence is an offence,” the report said.
“For Crown Servants [including ministers, civil servants and police] and government contractors, however, an unlawful disclosure related to one of the six categories must be deemed ‘damaging’ for it to constitute an offence.”
The law sets out “damage tests” that require the government to prove that UK’s national interests have been harmed for a case to proceed.
The maximum penalty for an unauthorised disclosure under the Act is two years' imprisonment or an unlimited fine, or both.
Anna Bradshaw, a partner at solicitors’ firm Peters and Peters, said the “damage” does not have to materialise for the law to be broken.
“It is potentially applicable to such a broad range of scenarios that the requirement for authorisation [from the director of public prosecutions or attorney general] acts as a safeguard against over-enthusiastic prosecutions,” she told The Independent.
“It’s difficult to imagine something that wouldn’t potentially be in scope of the law because of the wording of all the provisions. It’s deliberately drafted widely.”
High-profile cases include a case that saw a member of police staff jailed for eight months for passing a Sunday Times journalist information on planned al-Qaeda terror attacks in 2007.
Five years before, MI5 agent David Shayler was jailed for six months for selling information and documents on topics including the IRA and Communist Party of Great Britain to the Mail on Sunday.
In 1983, Foreign Office clerk Sarah Tisdall was given a six-month sentence for passing documents to The Guardian which gave the arrival date of missiles to an RAF base.
Who wants Mr Williamson to be investigated?
Mr Williamson has claimed he would be “exonerated” by a police investigation and some of his colleagues and supporters are unsatisfied with the lack of transparency in the Cabinet Office inquiry.
Former national security adviser Lord Ricketts told the BBC: “On the face of it, this is a breach of the Official Secrets Act. All the ministers and officials around the table will have signed that. So, it seems to me the police ought to be considering, is there a case to be considered there?
“It would be for the director of public prosecutions to make the decisions, not ministers.”
Labour has led calls for prosecution, with deputy leader Tom Watson telling the Today programme: “This is about the law applying equally and to everyone.
"We have had high-profile civil servants go to jail for breaching the Official Secrets Act. The logic of the prime minister's letter is she says she has compelling evidence that suggests he has done the same. He is denying it and he has the right to clear his name – the way to do that is a criminal inquiry if confidential information has leaked."
Vince Cable, the Liberal Democrat leader, echoed the demand, insisting: “This story cannot begin and end with dismissal from office."
He added: “What is at stake is the capacity of our security services to give advice at the highest level. This must now be referred to the Metropolitan Police for a thorough criminal investigation”
Liberal Democrat deputy leader Jo Swinson has written to Metropolitan Police Commissioner Cressida Dick to ask for a criminal investigation.
China's ambassador to the UK has urged the government to act independently and resist external pressure.
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