Don't know where to start on this statement... But what a load of bullocks!!!
Previous convictions don't get mentioned in a criminal trial.. A fine or a caution is an option for any police officer. And if more than one MP didn't get prosecuted for fiddling their expenses then why wouldn't CPS not let stokes off for something a lot less..
Finally, I would hope CPS don't prosecute people just because they are in a tricky spot...
Previous convictions are taken into account when issuing a caution for minor offences. Cautions require admission of guilt. What was (No Swearing Please) about the statement?
"A fine or a caution is an option for any police officer."
Also not true. Affray is an indictable offence.
Edit: Just reading your post back, I think you're confusing the trial part with the method of how an offence is dealt with. You are correct in saying previous convictions aren't mentioned in criminal trials, however, they most certainly are taken into account when deciding how a suspect is dealt with. It forms a core part of the CPS's public interest test.