Prince William paid a secret visit to Afghanistan to meet frontline British troops, his office said on Wednesday.

A spokesman said the 25-year-old prince, who was recently awarded his Royal Air Force (RAF) wings after a training course, flew a military transport plane for part of the journey to Kandahar.

He spent three hours with British service personnel at the airfield before returning to Britain, the spokesman said.

Permission for the confidential trip on Monday had been given by the Queen and Prince Charles.

The spokesman said: "The purpose of the trip was for the Prince to familiarise himself with the operations of the RAF in theatre."

Calling the confidential 30-hour trip a success, he said: "It passed without a hitch."

The prince flew in a C-17 Globemaster military transport plane which left a Royal Air Force base on Sunday, arriving in Afghanistan the next day. He flew back home via Qatar.

William's younger brother Harry served for 10 weeks with British troops in Helmand province earlier this year.

His tour of duty was abruptly cut short when a media blackout was broken. That prompted military chiefs to pull him out amid fears for his safety as a prime target for a Taliban attack.

William's secret trip came after four months of training with the Royal Air Force which ended at a graduation ceremony with him being presented with his wings by his father.

William and Harry's uncle, Prince Andrew, was a Sea King helicopter pilot during the 1982 Falklands war.