During the construction of the road, Hamilton became aware of the need for strong, adaptable
bridges with components that could easily be transported and erected in remote and/or difficult
terrain. With British Insulated Callenders Cables, now Balfour Beatty Power Networks Ltd, he designed the
Callender-Hamilton bridge system, the income from which helped support his family. The parts of the bridge were bolted together like a
Meccano set, and it was popular with the
British Army away from the battle front. The failure of the First World War
Inglis bridge led to the development of the
Bailey bridge. Hamilton successfully claimed to the
Royal Commission on Awards to Inventors that the Bailey bridge had breached his
patent. Because the Bailey bridge used a pin joining system similar to that used in the Martel Bridge designed by Lieutenant-General Sir
Giffard Le Quesne Martel, Hamilton told the commission the Bailey bridge should be called a 'Martel Mk2'. In 1936 the British
War Office paid Hamilton £4,000 for the free non-civil use of his Unit Construction Bridge. In 1954 the Commission awarded him £10,000 in respect of the bridges used in
South East Asia Command during WW2 in India. In 1955 Hamilton told the Commission that Martel deserved more than the £12,000 that Bailey had received. Martel was awarded £500.. == Callendar-Hamilton Aeroplane Shed ==