[addman]

Blenheims actually did some nightfighting during the war so it's not too out of this world BUT if it manoeuvres like UFO then something is wrong.

Long-range fighter

The Bristol Blenheim was used by both Bomber and Fighter Commands. Some 200 Mk I bombers were modified into Mk IF long-range fighters with 600 (Auxiliary Air Force) Squadron based at Hendon, the first squadron to take delivery of these variants in September 1938. By 1939, at least seven squadrons were operating these twin-engine fighters and within a few months, some 60 squadrons had experience of the type. The Mk IF proved to be slower and less nimble than expected, and by June 1940, daylight Blenheim losses were to cause concern for Fighter Command. It was then decided that the Mk IF would be relegated mainly to night fighter duties where No. 23 Squadron RAF who had already operated the type under night time conditions had better success.
[edit] Night fighter

In the German night bombing raid on London, 18 June 1940, Blenheims accounted for five German bombers thus proving they were better suited to a nocturnal role. In July, No. 600 Squadron, by then based at RAF Manston, had some of its Mk IFs equipped with AI Mk III radar. With this radar equipment, a Blenheim from the Fighter Interception Unit (FIU) at RAF Ford achieved the first success on the night of 2–3 July 1940, accounting for a Dornier Do 17 bomber. More successes came and, before long, the Blenheim proved itself invaluable in the night fighter role. Gradually, with the introduction of the Bristol Beaufighter in 1940-1941, the Blenheim was supplanted by its faster, better armed progeny.

http://en.wikipedia.org/wiki/Bristol_Blenheim