Prime Minister David Cameron has announced plans to spend an extra £2bn on the Herefordshire-based SAS and other special units over the next five years to improve their fighting capabilities.
It is understood that the money will not be used on a recruitment drive, but will fund new weapons and vehicles - possibly including helicopters - protective equipment, night-fighting kit and communications.
In his annual address to the Lord Mayor of London's Banquet, Mr Cameron said: "Britain, France and our allies around the world will never be cowed by terrorism. We will only redouble our resolve to defeat it."
The Prime Minister said the new National Security Strategy he is unveiling next week will give Britain the resources it needs to "increase both its hard and soft power" and boost its influence in the world.