It plunged into the ground at high speed before exploding, killing all five of its crew in a mystery crash.

Sixty years later, those on board Vickers Valiant WZ363 were remembered at a poignant ceremony as the sun shone down on a village cemetery near to where they were stationed.

The aircraft, part of the RAF's elite Cold War bomber force, took off from RAF Marham, near King's Lynn, for a routine training flight on the night of May 6, 1964.

Warrington Guardian: A Vickers Valiant, similar to the aircraft which crashed in May, 1964, killing its five crewA Vickers Valiant, similar to the aircraft which crashed in May, 1964, killing its five crew (Image: Submitted)

It plunged into a field on the outskirts of Market Rasen, in Lincolnshire, and the massive blast which followed left little evidence regarding what may have caused the crash, although the Valiant fleet was scrapped the following year after metal fatigue was found in a number of aircraft.

On board were the 49 Sqn aircraft were Flt Lt FC Welles, 26, from Sussex, who was the captain, Flt Lt GA Mills, 26, from Warrington, the co-pilot, Flt Lts LR Hawkins, 30 from Middlesex and JR Stringer, 37 from Hertfordshire, the navigators and Sgt R Noble, 25, from King's Lynn, who was an air electronics officer.

Warrington Guardian: Flowers laid at the grave of Flt Lt Hawkins in the cemetery at MarhamFlowers laid at the grave of Flt Lt Hawkins in the cemetery at Marham (Image: Chris Bishop)

Warrington Guardian: Personnel from RAF Marham at the service to remember five members of the bomber crew killed in a crash in 1964Personnel from RAF Marham at the service to remember five members of the bomber crew killed in a crash in 1964 (Image: Chris Bishop)

Warrington Guardian: RAF Marham commanding officer Group Capt Fred Wigglesworth salutes the fallen RAF Marham commanding officer Group Capt Fred Wigglesworth salutes the fallen (Image: Chris Bishop)

Flt Lt Welles, Flt Lt Hawkins, Flt Lt Stringer and Sgt Noble were buried in the cemetery at Marham, near the RAF base. Flt Lt Mills was buried in his home town of Warrington.

On Monday, personnel from Marham laid flowers at the grave of Flt Lt Hawkins.

Warrington Guardian: The letter from Tony Masche, received by RAF MarhamThe letter from Tony Masche, received by RAF Marham (Image: RAF Marham)

Warrington Guardian: The letter received by RAF Marham from Tony MascheThe letter received by RAF Marham from Tony Masche (Image: RAF Marham)

Group Capt Fred Wigglesworth, commanding officer at the base, said it had received a letter from Tony Masche, a childhood friend of one of the crew, who now lived in Queensland, Australia.

Mr Masche had asked for flowers to be laid at his friend's grave to remember the crew even enclosed £25 towards the cost of the tribute.

Warrington Guardian: The grave of Flt Lt Welles in the cemetery at MarhamThe grave of Flt Lt Welles in the cemetery at Marham (Image: Chris Bishop)

Warrington Guardian: The grave of Flt Lt Stringer in the cemetery at MarhamThe grave of Flt Lt Stringer in the cemetery at Marham (Image: Chris Bishop)

Warrington Guardian: The grave of Sgt Noble in the cemetery at MarhamThe grave of Sgt Noble in the cemetery at Marham (Image: Chris Bishop)

Warrington Guardian: The grave of Flt Lt Hawkins in the cemetery at MarhamThe grave of Flt Lt Hawkins in the cemetery at Marham (Image: Chris Bishop)

Flowers were laid by Charlie, a flight lieutenant from the modern-day 207 Sqn, which is now the operational conversion unit training pilots to fly the F-35 Lightning stealth fighters based at Marham.

CAUSE OF CRASH REMAINS A MYSTERY

Warrington Guardian: A Vickers Valiant which was on display at RAF Marham being removed from its stand in 1982A Vickers Valiant which was on display at RAF Marham being removed from its stand in 1982 (Image: Newsquest)

The Vickers Valiant was a part of the RAF's V-bomber strategic deterrence force in the 1950s and 60s.

The 600mph jet, of which 100 were built, could fly at heights of up to 55,000ft and carry nuclear weapons.

Valiant WZ363, from 49 Sqn was being flown by a crew from Marham-based 207 Sqn on the night of May 6, 1964.

It was due to carry out routine bombing practice on a range at Wainfleet, on the Wash, before carrying out a practice diversion north to Binbrook, near Market Rasen, for a dummy landing, before returning to Norfolk.

Warrington Guardian: Group Capt Fred Wigglesworth, commanding officer at RAF Marham, addresses the memorial serviceGroup Capt Fred Wigglesworth, commanding officer at RAF Marham, addresses the memorial service (Image: Chris Bishop)

An air traffic controller said it completed a "rolling landing" at Binbrook, before climbing to 700ft and being cleared to turn on a heading for Marham.

But contact was lost minutes later. A runway controller saw a flash on the horizon, followed by the muffled sound of an explosion.

Witnesses in Market Rasen said they saw flames as the aircraft went into a steep dive just before midnight, flying at 250 - 350mph.

Warrington Guardian: The memorial in the RAF section of the cemetery at MarhamThe memorial in the RAF section of the cemetery at Marham (Image: Chris Bishop)

It remains unclear to this day why the crew lost control. Remains of the aircraft were badly damaged by the impact, which caused a 20ft-deep crater and scattered wreckage over a wide area.

The crash happened a year before the Valiant, which entered service in 1956, was retired after cracks were found in the wing spars of a number of aircraft.

The defence secretary of the time decided the cost of repairs could not be justified and the fleet was scrapped in 1965.