The length of tours for key units of the British military serving in Afghanistan is likely to be doubled to a year for the crucial drawdown period leading to the end of combat operations there in 2014.
The "spine" of brigades sent in the future may be deployed for up to 12 months rather than six, the commander of Task Force Helmand, Brigadier Ed Davis, said.
The extension of tours will be highly controversial at a time when cuts are being made in numbers of personnel, and the Libyan mission means that British forces are engaged in fighting on two fronts, leading to complaints of overstretch.
Brigadier Davis, of 3 Commando Brigade Royal Marines, stressed that the continuing Taliban threat showed the need for longer deployment of some UK contingents, especially those "mentoring" Afghan forces, to provide more continuity - and that this necessitated much longer periods in Helmand.
He said: "The constant churn of people with whom you have really strong relationships is hard, so I think you need to reduce that by having people in theatre for longer.
"I suspect over time we'll see these changes and a larger percentage of people doing longer tours; we are looking at nine to 12 months."
If the move comes about it is likely to affect soldiers from Northern Ireland regiments who are involved in mentoring Afghan units.