Associated Equipment Company (AEC) was a British vehicle manufacturer that built buses, motorcoaches and trucks from 1912 until 1979.

As part of the reorganisation following the takeover, a separate concern was set up for the bus manufacturing elements, and was named Associated Equipment Company, better-known as AEC.

With the outbreak of World War I in 1914, AEC's ability to produce large numbers of vehicles using moving-track assembly lines, based on American principles,[1] became important in supplying the increasing need for army lorries.

AEC commenced large-scale production of their 3-ton Y-type lorry in 1916, including some with Daimler-built engines, badged and supplied as Daimler.

The Matador chassis was used as the basis for the Deacon a self-propelled 6-pounder anti-tank gun, which was used briefly in North Africa.

Four hundred AEC armoured command vehicles, popularly known as the "Dorchester" (after the hotel), were built on the Matador and Marshall chassis.

[5] The initials AEC remained on its vehicles, with the exception of some badge-engineered versions, such as the Crossley Regent bus.

In 1949 ACV acquired the bus coachbuilding company Park Royal Vehicles, along with its subsidiary Charles H Roe.

Park Royal designed a new cab for the AEC Mercury in the mid-1950s, which appeared on all models across the range about this time.

[8] The Thornycroft name disappeared from all the vehicles except the specialist airport crash tenders, such as the Nubian, and the Antar off-road tractor unit.

[12] In Spain, ACLOs could be seen mainly as double-deck buses in Barcelona, and as line coaches in ALSA fleet.

[citation needed] In Portugal, the AEC vehicles, mainly coaches and buses but also lorries, were assembled and bodied by UTIC, a large coachbuilding firm based in Lisbon and Oporto, and were marketed under the UTIC-AEC badge.

AEC based vehicles were market leaders in Portugal, for instance, by the time of creation of Rodoviária Nacional, in 1975, those accounted for 67.5% of the more than 2500 buses and coaches inherited fleet.

They were mechanically equivalent to a rear-engined Reliance or a coach version of the Swift 691 which AEC had planned but never marketed.

They were expensive to buy new and the square sided styling looked dated to British eyes in the age of the Elite and Dominant coaches, thus they were slow selling.

In the late 1950s, Spanish government restrictions on imports reduced AEC sales in Spain to virtually nil.

Nevertheless, the Leyland takeover in 1962 soon undermined the agreement, as Leyland was partnering with Barreiros's Spanish arch-rival, Pegaso; and eventually Barreiros looked for another collaborator in the bus arena, signing in 1967 an agreement with Belgian company Van Hool.

It was originally a 7/8 ton 4x2 lorry with a six-cylinder overhead valve engine developing 110 bhp (82 kW) on a wheelbase of 16 ft 7 in.

It remained in production until 1948 when it was superseded by the Mk III, which was mechanically similar, but had the Park Royal cab.

The Leyland Marathon (1973–79) was a high powered 4x2 or 6x4 tractor unit with a modified Ergomatic cab, which was built at the AEC factory in Southall.

AEC produced 9,620 artillery tractors; 514 6x6 bowsers for the Royal Air Force; 192 6x6 lorries (some of which had Coles Cranes mounted); and 185 similar vehicles, but 6x4, for mobile oxygen plants.

There was a final short run of the 0853 4x4 Matador for the Army in the early fifties, due to ongoing issues with the introduction of the replacement Leyland.

It was the biggest rally ever held by The AEC Society and was closed by a flypast by the Battle of Britain memorial flight.