What Do I Put? - From Ex Con

Hi. Considering I am getting zero help from my probation officer, I was wondering if any of you guys could advise?
I have been in prison for lets say quite a while and I am actively seeking work. The problem I have is my CV.
I have been on some interviews that require information about the gaps on your CV and why there are gaps in your CV. It is pretty obvious after spending time in jail that I do have gaps on my CV but how do I explain this?
I know many companies will show me the door if I tell them I have been in prison. All I want is a chance and there aint anybody out there willing to give me one. It makes me laugh that when you are in jail, those running it bleat on about rehabilitation yet do not prepare you for things like this and a CV these days, (as I have found out) is a major requirement for jobs. The application forms too seem to ask more and more personal questions too. If I write on my CV that I have served time in jail, you can bet your bottom dollar that it will be screwed up in to a ball and thrown in the bin. Have you any advise please? From Ex Con.