“Although badly wounded in his solar paddles,” wrote Hailsham to the PM, “he is not quite dead.”

“He still utters intermittently – sometimes intelligibly,” continued the minister. “He may still improve sufficiently to tell us something of value, though he can hardly say ‘merrily shall I live now’.”

Hailsham’s memo suggests that the UK’s financial loss from the project was relatively small compared to the US, who put up the bulk of the cash, and that the wounded satellite had already proved its scientific worth.

“We have got a great deal out of him during his life (short, but neither nasty nor brutish),” said Hailsham. “Before his accident he had transmitted for approximately a thousand hours, and it will take at least a year to analyse the significance of what he has said.”

Military use?

Ariel-1 was not the only satellite badly affected by the Starfish Prime nuclear explosion. The test has also been blamed for the premature failure of the world’s first TV communications satellite, Telstar.

But while Hailsham warned that: “the real moral about their high level explosion is the need for a test ban treaty”, military strategists noted the effects of the weapon with interest.