Recently I was on Metrolink and experienced the two ticket inspectors walking on the tram a couple times, and they cought someone without a ticket every time.

From what I am aware, the standard fare is £20 first offence, £40 seccond offence and £80 third offence, or something like that.

Fare dodging seems to be a national pastime, I know one or two people who openly boast about travelling without paying.