Mr Justice Rose said it was 'with great regret' that he dismissed an application by Paul and Ingeborg Sancto, of Holmside, Gillingham, Kent, challenging the Secretary of State's refusal to let them see a copy of the board of inquiry report on the death of their son, Kirk, 19.
The MoD traditionally maintains that its inquiry reports must always remain secret, in order to encourage servicemen to make a full disclosure to them.
But the judge said that Mr King's decision in May 1990 to keep this report secret had been 'outrageous', using the word in the context of a legal ruling relating to the power of the courts to interfere with a decision which is 'so outrageous in its defiance of logic or accepted moral standards that no sensible person who had applied his mind to the question to be decided could have arrived at it'.
The sapper died in June 1985 when two boats engaged in non-operational duties collided in Stanley Harbour in the Falkland Islands.
The judge ruled: 'The parents have no right to know how their son died in so far as this can be ascertained from the report.'
He added: 'That last sentence may well cause an astonished gasp from many members of the public and perhaps some ministers. But in my judgement it accurately reflects the state of the law. It follows that, with no enthusiasm at all, I am driven to the conclusion that, even in the unique and in some respects lamentable circumstances of this case, I cannot provide Mr and Mrs Sancto with the relief which, I have little doubt, most members of the public would feel is their due.
'It is not for me but for Parliament, where this judgment began, to remedy the situation.'
He contrasted this case with recent statements by ministers which had promised greater access to official information, saying it 'starkly' illustrated the extent to which those stated intentions were reflected by and capable of enforcement within the present state of the law.
The report and post-mortem report were sent to the coroner at Oxford, where the inquest was to be held.
In September 1986 there was a verdict of accidental death, but the contents of the board's report were never disclosed.
Mr and Mrs Sancto wrote to the Ministry of Defence asking for a copy but were told: 'Army investigation reports are confidential and cannot be disclosed outside the MoD.' But they were given a detailed account of the conclusion, which was that contributory causes of the accident included 'impairment of the crew's judgement by drink and the excessive speed' of their son's boat. The pathologist's report at the inquest showed no alcohol in his body.
The description in the Army report of the boat swerving at speed, with emergency stops, and passing over an anchor chain did not apparently relate to the final, fatal journey.
The judge said: 'The evidence at the inquest showed no great speed, lack of control or recklessness at the relevant time. There was evidence also given suggesting negligence in control of the harbour.'
After the judgment yesterday, Mr Sancto, an engineer who has spent many thousands of pounds fighting the case, said: 'We, as any other parents would be, are astounded. Any parent who finds their child has been killed and they are not entitled to know themselves the reasons why or the circumstances leading up to the death must be astounded.'