The Tower of London's first female Beefeater was allegedly subjected to a bullying campaign by some of her male colleagues, it was revealed today.

Two Beefeaters have been suspended and a third is under investigation over the alleged harassment of Moira Cameron.

Miss Cameron, 44, became the first female Yeoman Warder in the Tower's 1,000-year history two years ago.

Tower authorities launched an internal investigation over the weekend of October 24-25 in response to allegations of a number of specific instances of harassment.

It is understood that one person has received a police caution for defacing Miss Cameron's entry on online encyclopaedia Wikipedia.

Miss Cameron, from Argyll in Scotland, joined the Army at the age of 20 and served in Northern Ireland and Cyprus, rising to the rank of Warrant Officer Class 2.

She qualified to be a Yeoman Warder in July 2007 after completing the required minimum 22 years in the armed forces.

Miss Cameron, who has 34 male Beefeater colleagues, revealed that not everyone was welcoming when she started work at the Tower.

She said at the time: "I've had some comments. I had one chap at the gate one day who said he was completely and utterly against me doing the job.

"I said to him 'I would like to thank you for dismissing my 22 years' service in Her Majesty's Armed Forces'."

Her main duties are guarding the Tower - including the Crown Jewels - and welcoming tourists.

The Tower of London said in a statement: "We can confirm that three Yeoman Warders are under investigation in response to allegations of harassment. Two have been suspended.

"We take such allegations very seriously and our formal harassment policy makes it clear that this is totally unacceptable.

"We believe everyone is entitled to work in an environment free from any form of harassment, a principle that we expect all our staff to value and uphold.

"As soon as these allegations were brought to our attention, we immediately instigated procedures under our harassment policy.

"An internal investigation is already under way to establish whether these allegations have any foundation and should conclude within two to three weeks.

"Meanwhile, the Tower of London is a close-knit community and, understandably, this is a difficult time for us all."