BBC chief Tony Hall's death threat over sacking of Jeremy Clarkson
Police are investigating threats to kill BBC director-general Tony Hall, reportedly linked to his decision to axe Top Gear presenter Jeremy Clarkson.
Scotland Yard confirmed it was looking into allegations made last Wednesday, when Hall confirmed he would not be renewing Clarkson's contract because of his attack on producer Oisin Tymon at a North Yorkshire hotel.
The Mail on Sunday reported that the director-general - officially crossbench peer Lord Hall of Birkenhead - and wife Cynthia had been under 24-hour guard since the threat was received.
A security source told the newspaper: "There was a sudden urgency on Wednesday to find an eight-man security team to protect the Director-General of the BBC.
"A select group of close protection officers were approached and told that, as a direct result of the Top Gear punch-up and Jeremy Clarkson being sacked by the BBC, the DG had received a death threat.
"Some of the operation was visible, as a deterrent, while other bodyguards would have kept a very low profile."
It is understood the threat was sent by email. The Metropolitan Police said it appeared to have been sent from outside the UK, and inquiries are continuing to establish from where it was sent.
A Scotland Yard spokesman said: "Police in Westminster are investigating an allegation of threats to kill. The allegation was reported to police on Wednesday March 25. Inquiries continue. No arrests have been made."
The Mail on Sunday printed pictures showing security guards on patrol outside Mr Hall's Oxfordshire home, claiming it was costing £1,000-per-day to protect the BBC's top executive.
It also said that the BBC's head of security had asked for ex-special forces soldiers for the team.
Mr Hall, former chief executive of the Royal Opera House, took over the £450,000 BBC post in April 2013. A BBC spokeswoman said: "We wouldn't comment on security matters."