The Bristol Type 142 was designed by Frank Barnwell as a fast and spacious aeroplane for Lord Rothermere, the proprietor of The Daily Mail. Built by the Bristol Aeroplane Company, it was first flown at Filton on 12 April 1935. After some minor modifications, it caused a flurry of excitment during trials, as its top speed of 307mph topped that of any RAF fighter in service. When Lord Rothermere donated the aircraft to the Air Ministry for evaluation, they demanded exclusive rights to its production as a light bomber. The modified design became the Type 142M ('M' for 'Military') otherwise known as the Bristol Blenheim MkI.