Why Bristol was not the only integrated aircraft maker

Was Bristol the only British company that built both aircraft and engines?

No: Hawker also combined aircraft and engine interests through its merger with Armstrong Siddeley.

Bristol was not the only British company that combined airframe and engine production. Hawker's merger with Armstrong Siddeley placed an engine business inside the same wider industrial group. Formally it was a merger, although in practice it was close to a Hawker takeover. The distinction matters because the capabilities of an interwar aviation company could extend beyond the products sold under its best-known name.