Defence Secretary Des Browne has insisted RAF Nimrod aircraft are safe to fly despite a coroner's call for the entire fleet to be grounded.
The coroner, Andrew Walker, was speaking at the end of an inquest into the deaths of 14 servicemen in a Nimrod crash in Afghanistan in 2006.
He said the fleet had "never been airworthy" as he recorded narrative verdicts at the Oxford hearing.
But Mr Browne said changes made to the Nimrod meant it was now safe for crews.
Safety 'a priority'
In a statement, Mr Browne said: "The death of 14 brave servicemen in Afghanistan nearly two years ago was a profound and tragic accident, and my thoughts and sympathies are with their families today.
"The safety and security of our service personnel is an absolute priority for me.
The brother of Gerard Bell reacts to the coroner's verdict
"That is why I have sought the advice of the RAF's most senior officers and have been assured that the changes we have made to the Nimrod mean that it is safe to fly."
Earlier, the RAF's most senior engineer, Air Marshal Sir Barry Thornton, also maintained that serious design failures highlighted by the coroner had now been eradicated.
"These measures have been supplemented with enhanced aircraft maintenance and inspection procedures to ensure the aircraft, as it is today, is safe to fly," he added.
The BBC's Rob Watson said the coroner's ruling was "quite extraordinary" and would be embarrassing for the government.
"Clearly his judgement creates a huge problem and embarrassment for the Ministry of Defence, which has declared the aircraft safe and which sees the surveillance plane as vital to the mission in Afghanistan," our defence and security correspondent said.
Twelve of the men who died were from 120 Squadron based at RAF Kinloss in Moray. The two other victims were attached to the squadron.
Mr Walker, Assistant Deputy Coroner for Oxfordshire, said that opportunities to spot inherent dangers on the 37-year-old plane were missed and that a design fault which led to it exploding went unnoticed.
HOW THE NIMROD CRASHED
1. Nimrod refuels in mid-air
2. Possible fuel over-flow from number one tank
3.Second possible source of leak is pipe couplings behind number seven tank
4. Leaked fuel contacts hot pipe and ignites
5. Fire and smoke alarms triggered in bomb bay and underfloor by sensitive wiring
In his summing up, Mr Walker said in his view the entire Nimrod fleet had "never been airworthy from the first time it was released to service" nearly 40 years ago, but that the men could not have known this on the day of the crash.
The "cavalier approach to safety" which meant the design flaw was not recorded and acted upon "must come to an end", he said.
"I see no alternative but to report to the Secretary of State that the Nimrod fleet should not fly until the ALARP [as low as reasonably practicable] standards are met," he said.
The inquest had heard this was not expected before the end of 2008 and Mr Walker added he would not have made such a recommendation if there had not been plans to replace the Nimrod.
Graham Knight, a relative of one of those who died, agreed the Nimrod had been a risk "since day one" and said no more lives should be put at risk by flying the aircraft.
Robert Dicketts, the father of L/Cpl Oliver Simon Dicketts, who was also killed in the crash, criticised the MoD for describing the aircraft as "tolerably safe" during the inquest.
"I think that was really an insult - would you drive somebody's car that was tolerably safe?"
But armed forces minister Bob Ainsworth said the Chief of Air Staff Sir Glenn Torpy had "reaffirmed" the Nimrod was airworthy and that all the issues raised by the crash were being dealt with.
"The Nimrod is saving lives in operational theatres every day. However, if it was not safe we would not be flying it; it is safe with the measures we have taken and that is why we will not be grounding the fleet," he added.
The crash led to the biggest single loss of life suffered by the British military since the Falklands War.
An RAF Board of Inquiry (BoI) report into the incident concluded that ageing components and a lack of modern fire suppressants were among the "contributory factors" leading to the accident.
It said fuel probably escaped during the refuelling into a bay on the aircraft either because of a leaking fuel coupling or an overflowing fuel tank.
Relatives of the victims have voiced their anger over safety issues revealed by the inquiry and inquest, and have made their own investigations into the safety record of the fleet.
This week a senior engineer from defence and aerospace firm BAE Systems told the inquest that his predecessors, who made the Nimrod some 40 years ago, failed to fit a fire protection system on a key area of risk on the aircraft.
And the firm's head of airworthiness Tom McMichael said that if the evidence heard was correct, the Nimrod planes had, at the time of the tragedy, been flying in an unairworthy state for 37 years.
Following the crash all air-to-air refuelling on the Nimrod fleet was suspended. It was re-instated but suspended indefinitely following another incident over Afghanistan in November 2007.
After the inquest, the MoD said it placed the "highest priority on airworthiness and the safety" of personnel.
It said additional maintenance was taking place to ensure the Nimrod could be operated safely until its planned retirement from service.
The 14 men killed were:
Flight Lieutenant Steven Johnson, 38, from Collingham, Nottinghamshire, Flt Lt Leigh Anthony Mitchelmore, 28, from Bournemouth, Dorset, Flt Lt Gareth Rodney Nicholas, 40, from Redruth, Cornwall, Flt Lt Allan James Squires, 39, from Clatterbridge, Merseyside and Flt Lt Steven Swarbrick, 28, from Liverpool.
Flight Sergeant Gary Wayne Andrews, 48, from Tankerton, Kent, Flt Sgt Stephen Beattie, 42, from Dundee, Flt Sgt Gerard Martin Bell, 48, from Newport, Shropshire, and Flt Sgt Adrian Davies, 49, from Amersham, Buckinghamshire, Sergeant Benjamin James Knight, 25, from Bridgwater, Sgt John Joseph Langton, 29,from Liverpool and Sgt Gary Paul Quilliam, 42, from Manchester.
Lance Corporal Oliver Simon Dicketts, of the Parachute Regiment, from Wadhurst and Royal Marine Joseph David Windall, 22, from Hazlemere.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.