During development two prototypes were lost and the turboprop engines proved susceptible to inlet icing, which delayed entry into service while solutions were sought.

[4] This would have left the UK with little experience in transport construction at the end of the war, so in 1943, a committee under Lord Brabazon of Tara investigated the future British civilian airliner market.

[7] After wrangling between the Ministry of Supply and BOAC over costs, the go-ahead for the project assigned the company designation Model 175 in July 1948.

Senior figures within BOAC such as the Deputy Chairman Whitney Straight, however, considered the Proteus engine to be "an obsolete contraption".

The designation Britannia 101 was applied to first pair of prototypes, which were powered by the early Proteus 625, the successor to the 600 series engine that had already completed type trials.

[15] The snags were resolved and by September, the prototype was cleared to perform at the 1952 SBAC Display at Farnborough where spectators commented on the "quietness" of the giant airliner.

[16] After three de Havilland Comets crashed without explanation in 1953 and 1954, the Air Ministry demanded that the Britannia undergo lengthy tests.

[N 2] Finally, time was lost in resolving inlet icing issues (by selecting a different cruising height) that were discovered as the first aircraft were being delivered to BOAC.

[18][19][20] The first prototype G-ALBO was modified to more closely approximate a production standard, but was retained by the company to undergo engine testing and development.

[23] Australian airline Qantas considered the procurement of a Britannia fleet, however its protracted development eroded any competitive advantage against the Douglas DC-8 and de Havilland Comet 4.

[1] In 1956, Bristol's managing director Peter Masefield flew the tenth production Britannia, G-ANBJ, on a world sales tour.

However, the Americans wanted delivery within a couple of years, and Bristol, with its limited production facilities and the prior commitment to the BOAC order, could not meet that requirement, so, with the Boeing 707 and Douglas DC-8 jets expected in service by 1958-9, the opportunity passed.

The CL-44D4s were all built with swing-tails to allow straight-in cargo loading and served with a variety of carriers, most notably Flying Tiger Line.

The prominent modification was an enlarged fuselage, like the Mini Guppy, which was produced by Jack Conroy's previous company, Aero Spacelines.

[36] Following a long period of uneventful development flying trials and the fitting of a modified Proteus 765 series engine that greatly reduced breakdowns, a full Certificate of Airworthiness was awarded at the end of 1955.

[40] The Model 102 was eventually made available to other BOAC associates, including Cathay Pacific, Central Africa, East African, Nigeria and Malayan airlines.

[41] The 18 Bristol Britannia 312s for BOAC were delivered from September 1957 with its service introduction on the first-ever non-stop flight from London to Canada on 19 December 1957.

[45] In 1959, BOAC started flying the Britannia across the Pacific to Tokyo and Hong Kong, thus extending their network round the world.

[38] The westbound routing in 1959 for these intercontinental BOAC Britannia flights between the U.K. and Asia was London-New York-San Francisco-Honolulu-Wake Island-Tokyo-Hong Kong.

[53] Following the purchase of remaining spare parts from the Royal Aircraft Establishment and Cubana, Zaïrois airlines continued to operate several Britannias into the early 1990s on regular cargo flights from N'djili Airport to various destinations within the country.

[62] Passenger-only "stretched" version of the 200 series, incorporating 123 inches (3.1 m) longer fuselage, capable of carrying up to 139 (originally 99) passengers, medium-fuel capacity.