Maritime Comet Commander Courtney asked the Minister of Aviation to what extent it is practicable to convert existing Comet aircraft into the Maritime version; what would be the average cost of such conversion; and when it is intended to place an order for the production model of the Maritime Comet to replace the Shackleton. Mr. Roy Jenkins I would refer the hon. Member to the answer I gave to the hon. Members for Hendon, North (Sir Ian Orr-Ewing) and Mid Bedfordshire (Mr. Hastings) in reply to similar Questions.