The amount involved could be as much as six figures, it was claimed. Officers
are said to be planning to interview the former close friend referred to in
the threat.

Friends described Miss Ecclestone, whose 81-year-old father is Britain’s
fourth richest person with a $4.2 billion fortune, has being “horrified”
over the “quite intimidating” letter.

One source said: “Tamara has been really shaken up by all this.

“It has been a huge weight on her mind so she decided she had no option
but to go to the police.”

On Wednesday a Metropolitan Police spokesman confirmed the reports in the Daily
Mail
and
The Sun.

He said: “On Monday December 5 police from Kensington and Chelsea borough
received a complaint regarding an inappropriate communication relating to
the release of personal information.

“The allegation was assessed and is now being investigated at this early
stage as blackmail. CID in Kensington and Chelsea are investigating. No one
has been arrested. Inquiries continue.”

A spokesman for Miss Ecclestone told the newspapers: “Tamara is aware of
the matter and the police are handling it on her behalf.”

In August, her younger sister Petra, 23, was married in a £12million
extravaganza in Italy paid for by Mr Ecclestone and his ex-wife, former
Armani model Slavica, the mother of both heiresses.

Miss Ecclestone, whose parents divorced in 2009 after 23 years of marriage,
recently featured in the Channel 5 series Billion Dollar Girl, a three-part
documentary detailing her extravagant life.