It depends on the circumstances. In most cases, you must make a claim with three years of the injury occurring or the date which you became aware of the injury. If the injury happened before you turned 18 years, you have three years from your 18th birthday to make a claim.
If the injury resulted in you losing mental capacity, the three year time limit does not apply. But if you regain mental capacity, the three year clock will start from the date this occurred.
If the injured person passed away during the three year period then the three years starts again for date of passing.
If the claim is being brought only under the Armed Forces Compensation Scheme then the time limit is seven years.
If the claim relates to bullying and harassment you may have up to six years to bring your claim.
Despite these time limits we would suggest that you seek expert advice as soon as possible to allow your claim to be fully investigated and brought in time.