Rational (Heatley-Gresham)

Rational was a British automobile brand that was founded in 1901–1906 by Heatley-Gresham Engineering Co. Ltd. was built in Royston, Hertfordshire .

During this time, various car and taxi models were produced in small numbers.

source

• David Culshaw, Peter Horrobin: The Complete Catalog of British Cars. 1895-1975. New edition. Veloce Publishing plc., Dorchester 1997, ISBN 1-874105-93-6 .