Inmates at HMP Hull are celebrating after the gardens they tend won an award for being the best-kept in a prison in the country.The outdoor space is tended to by 20 prisoners, who say it has helped develop their sense of self worth.One prisoner Dave, said: "If it wasn't for this and being stuck in a cell all day, I don't think I'd be here today."The category B prison beat 15 other jails to win the Royal Horticultural Society's (RHS) Windlesham Trophy.