A light aircraft which crashed on the Queen's Sandringham estate had been stored outside for months unbeknown to its owners and its engine had corroded, an inquest has heard.

Two 'good friends' died when the Piper PA-28 aircraft came down in marshland near Wolferton, Norfolk, on September 11 last year.

Pilot Nigel Dodds, 58, and passenger Valerie Barnes, 73, both from Gateshead, died at the scene of multiple injuries, a post-mortem examination recorded.

An inquest in Norwich concluded they died as the result of an accident.

Robert Vickery, an Air Accidents Investigation Branch (AAIB) investigator, told Monday's hearing that the aircraft was owned by a syndicate to share costs and that this was 'quite normal'.

He said that, unbeknown to its owners, the plane was rolled outside at Newcastle between November 2015 and July 2016 when it was not being used, adding he did not know who rolled the plane out.

Mr Vickery said parts of the engine were found to have corroded.

The inquest heard that the plane crashed into an old sea wall after the engine failed during a flight from Southend to Newcastle, which was the final leg of a journey home from Menorca where retired company director Mr Dodds had a home.

He had transmitted a Mayday call while flying over The Wash, the estuary between Norfolk and Lincolnshire, stating he had a 'very rough running engine'.

He turned the plane back to the coast and told an emergency controller he could not reach the nearest airfield, stating: 'It's gonna be a field.'

An AAIB crash report concluded that the plane had likely stalled at a low height, from which there was insufficient height to recover, during an attempted forced landing following 'catastrophic engine failure'.

It found the engine had lost oil and was corroded.

PC Mark Whitmore, who was patrolling the Sandringham estate in an unmarked Land Rover, was called to the scene and pulled out a plastic window on the plane to try to help Mr Dodds and Ms Barnes.

'The plane had landed on a huge earth bank described as the sea wall,' he said, adding it soon became clear that both occupants had suffered 'catastrophic injuries'.

In a statement released after the inquest, the family of Mr Dodds said: 'This was a tragic accident which resulted in two good friends losing their lives because of catastrophic engine failure.

'The plane had been maintained appropriately and had a certificate of airworthiness as a result of checks using a Civil Aviation Authority programme and was described as sound and perfectly fit for purpose.

'During the course of the evidence given today the Air Accidents Investigation Branch commented more than once that Nigel had a reputation for doing things correctly and that they had been advised that he always took a long time to prepare the plane for take-off.

'The aircraft was overtaken by a very sudden emergency and Nigel did the best that could be done.'

The family added they were 'devastated' by the loss to both families but 'satisfied' with the inquest findings.