Scotland Yard will question No10 staff over the theft of Morgan McSweeney's phone, it has been revealed.
Mr McSweeney, who resigned as Sir Keir Starmer's chief of staff over Lord Mandelson's appointment as the UK's Ambassador to the US in February, lost the phone on October 20 last year.
A balaclava-clad man was said to have snatched the device from the Irishman's hand while travelling on an e-bike.
Mr McSweeney was replying to messages while walking home from a London restaurant at 10.30pm.
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However, the incident sparked concern given Mr McSweeney's close relationship with Lord Mandelson.
Scotland Yard will now speak to civil servants after reopening the investigation into the mugging incident.
Officers want to know whether No10 or the Cabinet Office still holds tracking data on the device, The Telegraph has revealed.
Mr McSweeney will be grilled by MPs on Tuesday after being called to appear at the Foreign Affairs Select Committee.
Morgan McSweeney, who resigned as Sir Keir Starmer's chief of staff over Lord Mandelson's appointment as the UK's Ambassador to the US in February, lost the phone on October 20 last year
|GETTY
The 49-year-old is expected to be challenged on the account given by former Foreign Office mandarin Sir Olly Robbins.
It has been suggested that Mr McSweeney told Sir Olly's predecessor, Sir Philip Barton, to "just f**king approve it".
However, Mr McSweeney has already rejected the suggestion that No10 put pressure on Foreign Office officials.
Speaking at a security conference earlier this week, the former No10 chief of staff said: "I find it strange reading about a character with the same name as mine sometimes."
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The Metropolitan Police confirmed its launching a new investigation
| GETTYMr McSweeney previously took “full responsibility” for giving Sir Keir advice that resulted in the “wrong” appointment decision when he resigned from Downing Street.
Meanwhile, the Prime Minister continues to dismiss calls to resign over Lord Mandelson's appointment.
Sir Keir said: "Last week, my political opponents were saying that there’s no way a civil servant wouldn’t have told me about the outcome of a developed vetting security exercise.
“Turns out my political opponents were completely wrong about that.”
Keir Starmer has already been criticised for appointing Lord Mandelson, who had links to paedophile Jeffery Epsetin | PA The Prime Minister added: “Then they said that I was dishonest. It turns out they were completely wrong about that.
"They are now putting any allegation they can and I will tell you for why – they are opposed politically to what this government is trying to achieve.”
However, Mr McSweeney's friendship with Lord Mandelson has raised concerns about the mobile phone holding messages about the New Labour grandee's appointment.
Scotland Yard opened a second investigation into the theft on March 27, after reports revealed the device was stolen.
No10 staff face being interviewed by police
| GETTYThe Prime Minister's political opponents appeared to initially suggest that elements of the phone theft incident did not add up.
However, Sir Keir responded: "Unfortunately, there are thefts like this.
"It was stolen. It was reported at the time, the police have acknowledged and confirmed that. That is what happened.
"The idea that somehow everybody could have seen that some time in the future there'd be a request for the phone is, to my mind, a little bit far-fetched."