FUTURE king Prince William and his long-term love Kate Middleton have split following the strain caused by the second in line to the throne's life in the Army.

The couple, who were widely tipped to marry, came to the shock decision earlier this week, but separated amicably with no one else involved, a source said.

William, 24, and 25-year-old Kate, who had been together for several years, faced huge pressures in the public spotlight, with Kate looking likely to one day be Queen.

A ''close friend'' of the Prince and Miss Middleton told The Sun newspaper: ''As far as Kate is concerned, William simply hasn't been paying her enough attention.

''She is stuck in London while he is living in an officer's mess in Dorset.

''Kate feels hugely frustrated that their relationship just seems to be going backwards at a rate of knots.'' A source confirmed the relationship had broken down, adding simply ''That's life.''

William passed out from Sandhurst as an Army officer last December and started his training to be a armoured troop commander in Camp Bovington, Dorset on March 16, leaving the couple seeing each other no more than once a week.

Just over a fortnight ago, the Prince partied with a blonde student at his barracks, having met at a nightclub in Bournemouth. Hampshire teenager, Lisa Agar, 19, later described him as a ''perfect gentleman''.

He was also pictured with his arm around an 18-year-old Brazilian student amid claims he had apparently cupped her breast in the photo.

William once declared he did not want to marry until he was 28 or 30.

Kate has endured intense media interest and recently made her first official complaint about harassment to the Press Complaints Commission over an image that appeared of her in the Daily Mirror.

She settled the matter after the paper apologised.

On her birthday in January, she faced a media scrum outside her London flat on her way to work and her lawyers said she was being followed on a daily basis.

News of the split will merely intensify the focus on Miss Middleton, who will be left without the security she enjoyed when out on the town with William and his accompanying police protection officers.

With the Prince now back on the market as one of the world's most eligible bachelor, there will be immense press interest on who will be the next woman to catch his eye.

Speculation had mounted that Kate, who works as an accessories buyer for Jigsaw, would be the one he would marry after she attended his graduation parade at Sandhurst in December.

It was the first time she had attended such a high profile event where the Queen and other senior members of the family were present.

But with news of their split, royal fans' hopes for a William and Kate wedding have been dashed.

Clarence House refused to discuss the matter. A spokesman for the Prince said: ''We don't comment on Prince William's private life.'' Miss Middleton left the family home in Buckleberry, Berkshire, just after 11 o'clock this morning.

Driven in a Land Rover Discovery and accompanied by family members she did not stop to speak to waiting media.

Wearing dark glasses and a light cotton shirt, she turned her face away from the cameras but smiled briefly before the car sped away.

Earlier family members at the rambling family home set in acres of lush countryside told reporters that ''we don't speak to the Press''.

It is thought that Miss Middleton sought refuge at her childhood home, a large but not ostentatious detached property surrounded by farmland, following news of her split with William.

The pair met at St Andrews University in 2001 where they were both studying history of art, although William in the end switched to geography.

It was Kate, who is six months older than William, who was credited with persuading him to continue his studies as he struggled to adjust during his first year.

The Prince once spent £200 for a front seat at a charity student fashion show where Miss Middleton took to the catwalk in a see-through lace dress which revealed her black underwear.

In the first year, they lived a few doors apart at St Salvators hall of residence and shared a house in the second year before later moving to a secluded cottage with two friends.

Rumours surfaced that the flatmates were romantically linked, but the first confirmation was when they were pictured on the slopes of the posh Swiss ski resort Klosters in March 2004.

Sensible and down to earth, Kate was pegged as an ideal royal consort, despite her lack of blue blood.

Given William's father's relationship history, royal watchers will be wondering whether there will be a chance of a Duchess of Cornwall type scenario - where the pair marry decades later.

Camilla first met the Prince of Wales in the 1970s, but later married Andrew Parker Bowles, then had an affair with the Prince and then finally wed the heir to the throne in 2005 and became an HRH.

Comparisons of Kate's treatment by photographers were made with that of Diana, Princess of Wales's experience.

In the early days of her relationship with Charles, Lady Diana Spencer was hounded outside her London flat and later became the most photographed woman in the world.