Wyvern 1845, when it became the crest of its unofficial coat of arms. The company asserted that the "wyvern was the standard of the Kingdom of Mercia", and that it was "a quartering in the town arms of Leicester". However, in 1897 the "Railway Magazine" noted that there appeared "to be no foundation that the wyvern was associated with the Kingdom of Mercia". A green Wyvern stands in the emblem of the ancient and historical umbrian city of Terni, the dragon is called by the citizens with the name of Thyrus. Sable wyvern on a white background with endorsed wings forms
Westland Wyvern (and equally troubled) Blackburn Firebrand. Several second-line squadrons also received Wyverns around this time. Total production was 127 airframes with 124 aircraft completed, as the last three Eagle piston-engined airframes, VR138, -139, and -140, were never completed. The first carrier trials were carried out by the first pre-production Wyvern TF.2 aboard on 21 June 1950. Despite this, when the Wyvern S.4 entered service with 813 Naval Air Squadron in May 1953, it had not obtained clearance for carrier operations, this being obtained only in April 1954. The Wyvern was in service with the Fleet Air Arm from 1954 to 1958.