The war in Afghanistan has given rise to a "warrior generation" of UK troops prepared for future conflicts, the head of the British Army has said.

Speaking on the centenary of Britain's entry into the First World War, General Sir Peter Wall, chief of the General Staff, said the military had learned from its decade-long operation in the war-torn nation.

The withdrawal of British troops from Afghanistan is well under way, with all combat personnel due to have left by the end of the year.

He told the Daily Telegraph: "I believe the warrior spirit and experience the British Army has acquired during its long decade of combat in Iraq and Afghanistan means it is ready for the challenges it is likely to face in the years ahead.

"We can be confident we have a 'warrior generation' who have the skill and fighting ability to play their role in the nation's defence and its security interests."

He also hinted that should the need arise, UK forces could return to Afghanistan.

He said: "It is vital that Afghan forces continue to deal with the any threat of al Qaida's return to the country. For if the Taliban were to be resurgent and al Qaida was again establishing sanctuaries, we would have to consider whether more effort was required on our part."

His comments also come as the Army faces a huge shake-up, with the Government's Army 2020 plan seeing the regulars cut by 20,000 to 82,000 and the number of part-time reservists being increased from 19,000 to 30,000.

In June, Gen Wall warned that any further cuts to defence spending could jeopardise the success of the reform and the Army's ability to defend Britain's interests.

"We will need all of our current resource allocation - and the freedom to reinvest savings in equipment support - if we are to deliver Army 2020 in a balanced manner and realise (then defence secretary Philip) Hammond's commitment to a firm foundation of men and materiel, well trained, well equipped and fully funded to operate in the nation's interests," he said.