Does An Official Secrets Act Expire?

Question: 
When I was 16 my first job was working with the Civil Service.  I had to sign the official secrets act. I was there for three years.  I’m 59 years old now.  Does it run out? Does it expire, is it indefinite?  
Mike, Romford

Answer:
Name: Jonathan, Reading
Qualification: Ex Military
Answer: There is no limit on the Official Secrets act.  If you want to go public with something - for example write a book - you need to get permission from the Attorney General.