Was it a leak or a hack?
The Foreign Office has repeatedly called the incident a "leak" rather than a "hack". It originally described the incident as "mischievous" but launched a formal inquiry on Sunday.
Foreign Office minister Sir Alan Duncan dismissed the idea that the disclosure was part of a conspiracy or "Brexit plan" and called it "a despicable leak," adding that "the first premise is that it is a leak from within".
A Whitehall source told The Times: "
The involvement of hostile state actors has not been ruled out" - but Downing Street said there is no evidence to suggest the involvement of foreign powers.
How many people had access to the emails?
Asked if ministers, MPs and special advisors would be investigated, the Foreign Office said that it will be for the inquiry to decide who is looked at.
On the question of how many people within government would typically see cables from an ambassador, Sir Alan said that although he was guessing, it could be around 100 people depending on classification.
An ex-British ambassador to the US and a close friend of Sir Kim's said there was a "possible range of villains" who potentially could have released the emails.
Sir Christopher Meyer told BBC Radio 4's Today programme: "It was clearly somebody who set out deliberately to sabotage Sir Kim's ambassadorship, to make his position untenable and to have him replaced by somebody more congenial to the leaker."
How do you investigate a leak?
In the Commons, there have been calls for the police to investigate amid widespread anger at the diplomatic fall-out.
Tom Tugendhat, chairman of the Commons foreign affairs committee, told MPs he had written to Metropolitan Police Commissioner Cressida Dick to "ask that a criminal investigation also be opened".
Sir Alan said police could become involved if evidence of wrongdoing over the leak is found, telling the Commons: "If evidence of criminality is found, then yes, the police could be involved."
In April,
following the Huawei leak, Lord O'Donnell, the former head of the Civil Service, revealed that officials in this type of situation may decide to investigate the mobile phone and e-mail records of people with access to the information to try to find who was responsible.
