This is a superb example of the VERY RARE Wrenn W2221 "Ludlow Castle" in BR Green Livery  issued by mistake by Wrenn, Basildon circa 1968. Once the factory had realised the mistake they were recalled from retailers at that time. The "Ludlow Castle" came in an early Period 1 box, had Hornby Dublo transfers, all pertaining to a " Cardiff Castle" fit, including running number and box stamp.(one end). The "Ludlow Castle" was supplied with an early Period 1 blue Instruction Manual, and underneath of the box is coloured yellow. 

Although no factory records exist of how many were produced (or returned) experience indicates that less than 25 genuine versions have been seen over the years.NOTE ; they were ALL issued by Basildon in a Period 1 box with one stapled end and with yellow coloured base.