2.  The provisions of the 70 miles per hour, 60 miles per hour and 50 miles per hour (Temporary Speed Limit) Order 1977, as varied by the 70 miles per hour, 60 miles per hour and 50 miles per hour (Temporary Speed Limit) (Variation) Order 1978, (which Order, as so varied, imposes during the period from 31st May 1977 to 30th November 1978 a general speed limit of 70 mph on dual carriageway roads (not being motorways), a general speed limit of 60 mph on single carriageway roads (not being motorways) and speed limits of 60 mph on certain specified dual carriageway roads and of 50 mph on certain specified single carriageway roads) are hereby continued indefinitely.