The admission is contained in a discussion document released by the British Ministry of Defence after a request under the Freedom of Information Act.
The six-month study, covering the period 1968-2005, was prepared under the direction of the then British chief of general staff, General Mike Jackson.
It describes the IRA as "a professional, dedicated, highly skilled and resilient force", while Unionist death squads and other republican groups are described as "little more than a collection of gangsters".
For the first time they have admitted that they did not defeat the IRA.
Republicans have known this for a long time, even if some British supporters were deluded enough to believe that the IRA were defeated.
A period of prolonged conflict have been engaged and it lead to a stalemate with neither the Brits nor the IRA able to land the killer blow.
The IRA then took the courageous decision to try and end the stalemate, they went down the political path. The rest they say is history.
The IRA are unbowed and unbroken and that is how they will remain