Chelsy Davy announced the end of her five-year relationship to Prince Harry on Facebook 

Prince Harry and Chelsy Davy have called it quits again.

Her online profile was altered to say: “Relationship: Not in one.” As is customary with Facebook, all Miss Davy’s friends received a red broken heart graphic telling them that her relationship with the third in line to the throne had come to an end.

They broke up temporarily at the end of 2007, after Prince Harry missed her 22nd birthday to go to a rugby match in Paris and Davy did not change her Facebook status.

Their relationship had become increasingly strained by the long periods of separation. Davy, 23, the daughter of a millionaire safari operator in Zimbabwe, is studying law at Leeds University.

Prince Harry, 24 has joined the Army Air Corps to train as a helicopter pilot – which will be a minimum two-year course – leading to even longer periods apart.

The Prince has also been spending more of his free time partying with his Army friends, to the irritation of Davy.

The relationship had been showing signs of strain since the couple reunited after a separation in 2007. In September that year, Harry left his girlfriend fuming after he was 40 minutes late to meet her at Heathrow. A month later it was reported that they had separated after he missed her birthday party to go to the Rugby World Cup final.

One informed source said: “They are two young people who have gone their separate ways for good. The relationship had run its course. It is entirely amicable and they hope to remain friends. Prince Harry still feels very protective of Chelsy and hopes that the media gives her some privacy.”

The couple broke up before Prince Harry started his course at Middle Wallop army base in Hampshire last Monday. The split was disclosed on the News of World website on Saturday afternoon.

This break up marks the end of the young Prince’s first serious relationship.

The focus will now switch to Prince William, who has been dating Kate Middleton since they met at St Andrews University in Scotland. His decision to join the RAF to train as a search and rescue pilot for three years has made the prospect of a Royal marriage seem much less likely.