For the county constituencies of Arundel, Chichester, Horsham, Mid Sussex and Shoreham and the borough constituencies of Crawley and Worthing as constituted by the Schedule to the 1983 Order (and described by reference to local government areas as they existed on 5th May 1983 in respect of the constituencies of Arundel and Mid Sussex and those parts of the constituencies of Crawley and Shoreham which consist of wards of the Districts of Arun and Mid Sussex and 1st February 1983 in respect of the remainder of those constituencies and the constituencies of Chichester, Horsham and Worthing), there shall be substituted the constituencies which are named on the left-hand side of Part I of the Schedule to this Order and comprise the areas as set out on the right-hand side, which areas are:—
(a) in the case of the Rustington North and Rustington South wards of the District of Arun, those wards as they will exist on 7th May 1987 when Article 13 of the Arun (Parishes) Order 1985 comes into force, and
(b) in the case of the remaining areas, local government areas as they existed on 9th February 1987 (and accordingly as altered by the Adur, Arun and Worthing (Areas) Order 1985 , the Arun (Parishes) Order 1985, the Arun and Chichester (Areas) Order 1985 , the Crawley, Horsham and Mid Sussex (Areas) Order 1982 , the Horsham and Mid Sussex (Areas) Order 1985 and the Mid Sussex (Parishes) Order 1985 ).