Details of the “personal issues” that forced shadow chancellor Alan Johnson to quit were starting to emerge today amid allegations that the politician's bodyguard had an affair with his wife.
Mr Johnson's close protection officer when he was home secretary, Paul Rice, is facing an internal Scotland Yard inquiry over his alleged behaviour.
A decision is expected to be taken shortly on whether the constable will be suspended or relieved of duty while the probe takes place.
Mr Johnson dramatically resigned from the Labour front bench last night, saying he was finding it “difficult to cope” with “personal issues in my private life”.
Responding to reports that Laura Johnson had an affair with Mr Rice, a Yard spokesman said: “Certain matters regarding a Metropolitan Police Service Pc were referred to the directorate of professional standards.
“We are not in a position to discuss further at this time. No officer is suspended or relieved of duties at this time.”
Mr Rice is said to be deployed protecting current Home Secretary Theresa May.
Mr Johnson's spokesman has refused to comment on the claims, while the Home Office said it did not comment on personal security matters.
Shadow minister Tessa Jowell told BBC2's Newsnight she did not know why Mr Johnson had re
signed, but added: “He's clearly very distressed. It's clearly a very, very difficult time for him.”
In his statement, Mr Johnson said only that it was “to do with my family”.
“I have found it difficult to cope with these personal issues in my private life whilst carrying out an important frontbench role,” he added.
Mr Johnson has been married to his second wife Laura for almost 20 years and the couple have a 10-year-old son.
His resignation left Ed Miliband facing his biggest test since being elected Labour leader, forcing him to reshuffle his shadow cabinet less than four months into the job.
He installed Ed Balls as shadow chancellor after overlooking him last October.