DOUGLAS DC-4s were an extremely rare sight at Heathrow by the mid-60s.

In the airport's formative years, such planes had been regular visitors, but the arrival of the jet age and the introduction of more sophisticated turboprop aircraft combined to push these piston-engined workhorses to the sidelines.

When the one pictured, a DC-4 Skymaster, touched down in 1965, word soon got around the plane-spotting fraternity and, like twitchers excitedly flocking to catch a glimpse of a rare bird, large numbers descended on the airport to see this unusual visitor.

There was some mystery as to why it was in the livery of Alitalia but carrying an Irish registration, EI-ANL.

The reason was that it was operated by Shannon Air, who had signed a lucrative deal with the Italian airline to operate all its scheduled freight flights to Britain.

November Lima became a regular visitor to Heathrow, providing younger aviation enthusiasts with a taste of how 'real planes' looked and sounded. All went well for several months, but with the onset of winter the amount of cargo being carried by the DC-4 dropped significantly.

The old plane continued plodding

between Italy and London, but the freight hold was sometimes almost empty.

Things came to a head in February of 1966. Shannon Air, financed by a US-based firm, had failed to pay landing fees to the British Airports Authority. As a result, the aircraft was impounded and for several months it became a fixture on

Heathrow's southside while discussions went on to try to resolve the situation.

Shannon Air managed to scrape together half the sum owed and the DC-4 was at last allowed to leave - by which time it had been seen by virtually every member of the plane-spotting fraternity for miles around.

Shannon Air ceased operations soon afterwards, but it was not the end for the DC-4, which had originally been delivered to Northwest Airlines in the US during 1946, remaining with them until 1958, then seeing service with Trek Airways and Luxair before being leased by Shannon Air in 1964.

It found a new lease of life with

another Irish charter airline, Aer Turas, was given the grand name of Monarch of Munster and went on to fly cargo all around Europe, before ending its days with an US-based oil company.

It was finally withdrawn from use in Malta in 1977, but even then went on to serve a purpose as a fire trainer, before being broken up in 1985.