I have never been arrested but when I applied to join the Police Specials, the application form did ask whether you or anyone in your family have been arrested in the past and if so what was the offense.
If you have not been in trouble since then I don't think it would be a problem providing it wasn't for anything serious. For example rape , murder, burglary.
From the experience I had of the application process I think they want people that have life experience and I am sure if you can say that fair enough you got into trouble but learnt from it then you should be okay.
Good luck in your application.