David Cameron has been forced to cancel a visit to a forward British military base in Afghanistan amid concerns of a possible Taliban attack.
A spokesman for the Ministry of Defence said: "We can confirm that there was a change to the Prime Minister's original visit schedule today. Afghanistan is a dynamic operational environment and as a result changes are made to schedules at the last minute."
The base was in an area which was previously an insurgent stronghold and which was heavily contested in the recent Operation Moshtarak offensive in central Helmand.
Mr Cameron, who earlier held talks in Kabul with Afghan President Hamid Karzai, was able to visit an agricultural school near the provincial capital built with £1.2 million of British funding, and held talks with the provincial governor.
The PM warned that the international coalition in Afghanistan was facing a "vital year" as he made his first visit to the country since becoming Prime Minister.
Mr Cameron acknowledged that the public needed to see "real and noticeable and marked" progress in the coming months if they were to continue to support the mission.
He announced that he was providing an additional £67 million to counter the threat of deadly roadside bombs or IEDs, saying ensuring British forces were properly equipped was his "biggest duty" as Prime Minister.
But while he emphasised the need to ensure that al Qaida could not make a return to Afghanistan, he said that he did not want to keep British troops there "a moment longer than is necessary".
