A letter sent to St James’s Palace containing a substance is being investigated by police.

The Met Police tested it and said it was not harmful. No arrests have been made and inquiries are ongoing.

The Evening Standard reports the letter was addressed to Prince Harry and his fiancée, Meghan Markle.

It was received on February 12 – the day before a package containing white powder was sent to the Palace of Westminster.

It is alleged the substance sent to St James’s Palace was also white powder. Officers are looking into whether or not the two packages are linked.

Police are also investigating an allegation of malicious communications in relation to the letter.