SIR Basil Blackwell issued a public apology after he inadvertently insulted the Duke of Edinburgh.

The head of the Blackwell publishing empire was presiding at Oxford Magistrates’ Court in 1958 when he was irritated by an aircraft passing overhead.

Sir Basil told a witness who was giving evidence in the court at Oxford Town Hall: “Wait until that infernal machine has gone.”

What he didn’t realise was that it was a Royal Navy helicopter and the pilot was the Duke on his way to engagements in Oxford.

After his court comment appeared in the Oxford Mail, Sir Basil wrote a letter to the paper expressing his regret.

He wrote: “I am dismayed to learn that a remark of mine in the magistrates’ court, with reference to what I took to be a low-flying bomber from Shippon Aerodrome, applied to the helicopter in which HRH the Duke of Edinburgh travelled to Oxford.

“Had I been aware that our Royal visitor was to come by air, it would have been pleasant to adjourn the court for a few minutes so that all might join in the welcome. And, of course, on such glorious occasions, the more noise, the merrier.”

The Duke spent six hours in Oxford that day, handing charters to Nuffield College and St Edmund Hall and visiting University College.

He was greeted by a crowd of more than 500 when he landed the helicopter at Merton Fields, after a flight from Buckingham Palace.

The Oxford Mail reported: “The crowd included a large party of Australian girls visiting Oxford, and a large number of undergraduates, some of whom were perched precariously on Merton College roof gables.”

At Nuffield College, the Duke met the founder, Lord Nuffield, and other dignitaries, but also spent time talking to 50 employees of Benfield and Loxley, the Oxford firm responsible for the building.

He asked the workers where the stone for the building had come from – “from Clipsham” – and if it had been difficult to get tradesmen – “yes”.

Then, after assurances that the college had been well built, amid bursts of laughter, came a typical quip from the Duke: “There’s no fear of it falling down, then?”

During his speech at Nuffield, the Duke paid tribute to Lord Nuffield’s benevolence in creating the college and expressed the hope that it would lead to new fields of study and research.

After visiting St Edmund Hall and University College, he returned to Merton Fields and waving to the crowd, climbed into the cockpit and flew the helicopter to Windsor.