In 1940 the civil engineer Guy Maunsell wrote to the War Office with a proposal for an artificial harbour, but the idea was not adopted.
Following Winston Churchill's memo Piers For Use On Beaches, dated 30 May 1942, the Mulberry project gained momentum under the direction of Major General D J McMullen and civil engineer Brigadier Bruce White.
[5] Hughes designed and supervised construction of a prototype jetty consisting of 'Hippo' concrete caissons sunk on the sea bed supporting 'Crocodile' steel roadway bridge units which spanned between the Hippos.
[6] During the testing a storm washed away the Swiss Roll and created scour of the sea bed around the Hippo units, which in turn led to them tilting, resulting in the failure of the Crocodile spans.
[7] In June 1943 the War Office set up a committee of civil engineers to advise on the design of the artificial harbours and the equipment to be used in them.