An envelope containing a suspicious white powder was sent to Prince Harry and fiancee Meghan Markle at St James' Palace.

The letter is understood to have triggered a full security scare at the palace but tests later revealed the powder was harmless.

Fears of an anthrax attack led counter-terror police to launch an urgent investigation, reports the Evening Standard .

Security measures at the palace mean the powder was detected before the letter reached the royal and his soon-to-be bride, American actress Meghan Marklle.

However they are understood to have been made aware of the incident.

A Met Police spokesman said: "Police are investigating after a package containing a substance was delivered to St James's Palace on Monday, February 12. The substance was tested and confirmed as non suspicious.

Prince Harry and Meghan Markle were made aware of the letter

"Officers are also investigating an allegation of malicious communications which relates to the same package."

Police have not yet made any arrests as enquiries into the incident continue.

On February 13, a letter containing a white powder was also sent to Home Secretary Amber Rudd at her parliamentary address.

Ms Rudd happened to be in America at the time of the incident, which forced a shut down of some offices while police investigated.

A spokesman for the Royal Family declined to comment on the incident.

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