In a lengthy and strongly-worded statement, Harry's Communications Secretary Jason Knauf outlined the difficulties Miss Markle had experienced since news of their relationship broke.

Mr Knauf said "The past week has seen a line crossed. His girlfriend, Meghan Markle, has been subject to a wave of abuse and harassment."

He added: " Prince Harry is worried about Ms Markle's safety and is deeply disappointed that he has not been able to protect her."

It is the first official confirmation from Kensington Palace that the pair are dating.

Mr Knauf said the Suits star had experienced "the smear on the front page of a national newspaper; the racial undertones of comment pieces; and the outright sexism and racism of social media trolls and web article comments".

He added that there had also been attempts by members of the press to get into her home.

The press aide said Ms Markle had endured "nightly legal battles to keep defamatory stories out of papers; her mother having to struggle past photographers in order to get to her front door; the attempts of reporters and photographers to gain illegal entry to her home and the calls to police that followed; the substantial bribes offered by papers to her ex-boyfriend; the bombardment of nearly every friend, co-worker, and loved one in her life."

Mr Knauf said Harry has, since a child, been very aware of the warmth of public feeling towards him and had to "develop a thick skin" about press interest in his private life, but the Prince felt a line had been crossed and asked for the statement to be issued to prevent any further damage.

"Prince Harry is worried about Ms Markle's safety and is deeply disappointed that he has not been able to protect her" he said.

"It is not right that, a few months into a relationship with him, that Ms Markle should be subjected to such a storm. He knows commentators will say this is 'the price she has to pay' and that 'this is all part of the game'. He strongly disagrees. This is not a game - it is her life and his.

"He has asked for this statement to be issued in the hopes that those in the press who have been driving this story can pause and reflect before any further damage is done. He knows that it is unusual to issue a statement like this, but hopes that fair-minded people will understand why he has felt it necessary to speak publicly."

Harry's late mother, Diana Princess of Wales, died in a car crash nearly 20 years ago after being pursued by the paparazzi, and he grew up fully aware of the impact of the intense media intrusion on her daily life.

As a young man, he was seen scuffling with a paparazzi photographer.

The 32-year-old former soldier is, however, canny enough to keep the press on side as he promotes his charitable interests and is usually relaxed and at ease in front of the cameras when carrying out public engagements.

News of the royal romance emerged just over a week ago when The Sunday Express reported the pair met in May while Harry was in Canada promoting Invictus Games 2017, the paralympics-style competition for injured servicemen and women and veterans he founded.

Kensington Palace initially said it would not be commenting on private matters.

Toronto-based star Markle neither confirmed nor denied the relationship, but shared a picture of two embracing bananas on Instagram and described herself as the "luckiest girl in the world'' in an interview.

Although linked to a number of women including singer Ellie Goulding and Camilla Thurlow, Harry has been an eligible bachelor since he split from long-term girlfriend Cressida Bonas more than two years ago.

The official confirmation that Harry and Markle are together may do little to detract attention away from their relationship.

Bookmakers Ladrokes has already issued new odds of 5 to 4 that they will walk down the aisle.

Jessica Bridge, of Ladbrokes said: "It must be love for both Prince Harry and Kensington Palace to publicly confirm the news, and we've been left with little option but to think that Meghan is the one and they're destined for their happily ever after."

Prince William, just like his brother Harry, spoke out over the behaviour of photographers in a bid to protect Kate Middleton when she was his girlfriend.

He expressed frustration in 2007 - when he and Kate were dating - after they were aggressively pursued in their car by the paparazzi.

Clarence House said second-in-line to the throne William was left concerned and angry by "threatening behaviour". It came at a time when William had rekindled his relationship with Kate after a brief split and the pair were said to have been more in love than ever.

Two years later in December 2009, the Queen's lawyers warned newspapers against publishing paparazzi photos of the Royal family, fuelling speculation William and Kate were to wed. Within a year, the prince had popped the question and their engagement was announced.