According to reports, the couple had only been able to see each other once a week in recent times due to Prince William's busy army schedule.
Friends of the couple have also hinted that his reluctance to marry Miss Middleton played a key part in the end of their relationship, with the 24-year-old prince said to have become increasingly concerned at media speculation that he was planning to propose to his 25-year-old university sweetheart.
One friend of Prince William and Miss Middleton, who became friends in 2001 while studying at the University of St Andrews in Fife, told the Sunday Times that the couple had met "five years too early", while another told the paper that the second in line to the throne needed to "live his life a bit".
Recent reports regarding the prince's social life are also said to have caused a strain in the couple's relationship, with the royal army officer pictured with a blonde student following a visit to a Bournemouth night club a fortnight ago.
Others have indicated that senior members of the royal family prompted Prince William to split with Miss Middleton, an assistant accessories buyer for fashion brand Jigsaw.
His father Prince Charles is said to have expressed concern to his son that it was unfair to prolong his relationship with Miss Middleton, who has faced increasing attention from the paparazzi, if he had no intention of marrying her.
"Prince Charles has suggested to him that it would not be fair to keep Kate hanging on if he was not prepared to marry her sooner rather than later," one source told the Sunday Telegraph.
Meanwhile, the News of the World, citing a royal courtier, has claimed that the Queen warned her grandson not to "rush down the aisle" at a recent secret "royal summit" to discuss his future.
Clarence House has yet to comment on the split between Prince William and Miss Middleton, who began dating around Christmas 2003.
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