British troops could remain engaged in operations in Afghanistan for another five years, the head of the Army has warned.

General Sir Richard Dannatt, the outgoing chief of the general staff, said it would take “a bit of time” before Afghan forces were able to take over responsibility for security in the country.

His comments came as the Ministry of Defence released figures showing that 94 British troops were wounded in action last month — more than double the 46 injured in June.

The MoD also named two of the five soldiers killed over the weekend, taking the total death toll since the start of operations in Afghanistan past the 200 mark to 204.

Private Richard Hunt, 21, of The 2nd Battalion The Royal Welsh, died at the military hospital in Selly Oak on Saturday, having been injured on patrol near Musa Qaleh in Helmand province three days earlier.

Sergeant Simon Valentine of 2nd Battalion The Royal Regiment of Fusiliers was killed in an explosion while taking part in a foot patrol near Sangin in Helmand on Saturday.

The latest casualty figures for July reflect the bloodiest month of the campaign for British forces - marked by the Operation Panther's Claw offensive to drive the Taliban from central Helmand ahead of this week's presidential election.

They show that 19 soldiers were very seriously injured, although not all in action, while the total number wounded in action for the year so far has reached 236, overtaking the 235 recorded for the whole of 2008.

Gen Dannatt, who was attending the official opening of a new Army recovery centre for injured soldiers in Edinburgh, said the troops in Afghanistan were engaged on a “difficult and dangerous” mission but it was essential they were successful.

He acknowledged however that it would take time before the Afghan forces would be trained and ready to take over from the British and other international forces currently in the country.

“We have got to get it right. It will take a bit of time. We will go on doing, as the military, what we need to do until the Afghan capability is good enough to take over from us,” he told BBC News.

“That will continue for years. I don't want to put a figure on that, but certainly two to four years, three to five years, of this kind of level of commitment by the military.”

He said Afghanistan would continue to require development assistance for many years after that.

“Twenty, 30, 40 years - who knows how long it will take?” he said.

Earlier, Defence Secretary Bob Ainsworth - who suggested at the weekend that the UK's mission could change “over the next couple of years” as the Afghan forces took on more responsibility - stressed he was not proposing a specific timetable.

“I don't think I can tie myself to a specific timetable. Over the next couple of years I profoundly believe that we can make progress in Afghanistan,” he said.

“That isn't to say that we will be able to draw back entirely, but I think we will see them (the Afghans) taking a growing share of the responsibility.”

Meanwhile Gen Dannatt's successor, General Sir David Richards, sought to clarify remarks he made in a recent interview in which he suggested that process under way in Afghanistan could take another 30 to 40 years.

Gen Richards, who takes over as Chief of the General Staff at the end of the month, said he had been referring to the wider mission - including development aid and reconstruction - and not the UK military campaign which would be much shorter.

“Afghanistan will need international help for many years to come - for example through development, governance and security sector reform - and I am sure the UK will play a part in that,” he said.

“But a British military force along current lines should only be needed for a much shorter period.

“There is no difference between my views and those of the Secretary of State on this. It is unhelpful to all those engaged in this conflict, both here and in Afghanistan, to suggest that there is.”