For 19 years Peter Wilkinson has occupied a unique position in broadcasting as the Queen's personal cameraman. When Her Majesty is on duty, he is usually alongside her capturing the scene at her engagements and during official audiences.

Employed by the BBC, ITV and Sky, Wilkinson is regarded with great affection by the Queen, who jokingly refers to the grey-haired grandfather as 'the silver fox'.

To mark his 50 years in television, an ITV camera crew followed him last year for a documentary: Cameraman To The Queen. It was broadcast immediately after the Queen's Christmas Message on Christmas Day.

Tension: The Queen and President Xi Jinping at a state banquet at Buckingham Palace last year

The Queen allowed him the privilege of having his own private premiere of the documentary, along with a drinks party, in the royal cinema on the ground floor of Buckingham Palace.

Yet this is the man — in whom the Queen invests an extraordinary amount of trust — who unwittingly plunged her into two major diplomatic rows on the same day this week.

First, during a Buckingham Palace reception on Tuesday, he caught the Queen on camera with David Cameron just as the PM was saying how Afghanistan and Nigeria were 'fantastically corrupt'.

Then, just hours later at the first Buckingham Palace garden party of the season, Wilkinson filmed the Queen talking to the senior Met Police officer who had been in charge of security for the Chinese state visit to Britain last October.

After the officer described how, ahead of the visit, Chinese officials had stormed out of a meeting with the British ambassador, warning they were going to call off the trip, the Queen made her views clear.

'They were very rude to the ambassador… extraordinary,' she said.

The political repercussions of the comments are still being felt, with the state-linked Global Times of China newspaper yesterday lashing out at the 'reckless gossip fiends and barbarians' of the British media.

To describe 70-year-old Peter Wilkinson — urbane and charming — as a barbarian fiend could not be farther from the truth, of course. But his unwelcome moment in the spotlight this week raises questions.

First, what is it about the Chinese that could have provoked the Queen to abandon the diplomatic niceties for which she is so famous?

The Queen was recorded telling Met Commander Lucy D'Orsi that Chinese officials were 'very rude' during last year's state visit

And second, how did the Queen's comments filmed by Wilkinson — for two decades a master of discretion — ever come to be aired?

It was in February last year that Buckingham Palace announced there would be a state visit the following October. The advance party arrived from Beijing in the summer, bristling with demands about security, accommodation and food.

Senior members of the party were to be quartered at the five-star Mandarin Oriental Hotel in Knightsbridge, as opposed to Buckingham Palace, where President Xi Jinping, his wife Peng Liyuan and their immediate but more junior support staff would stay.

The President and his wife were allocated the lavish Belgian suite, as is customary for heads of state.

Named after King Leopold I of the Belgians — Queen Victoria's uncle — it was used by the Queen and Prince Philip early in their marriage. Prince Andrew and Prince Edward were born there.

True, there had been an issue with the suite — a large section of the ceiling in an adjoining corridor had collapsed after a water leak. Industrial-strength humidifiers were used for weeks to dry it out.

The Queen has been caught out by her own cameraman making unguarded comments about last year's politically sensitive Chinese state visit

Yet the problem for the Chinese delegation was that the bedroom apartment — though luxurious enough for William and Kate to spend their wedding night there — has no ensuite bathroom.

There were also complaints about the Palace accommodation for the President's support staff.

The delegation insisted it must be arranged to incorporate the requirements of feng shui, the ancient Chinese science of 'harmonising good energy'. It meant repositioning beds, sofas, chairs and, if necessary, removing mirrors and pictures.

Bizarrely, the Chinese even asked for wardrobes to be painted red.

There were also difficulties over food. The menu for the main state banquet had to be approved in advance. But the President's support staff, in addition, brought their own food into the Palace. 'Apparently they were suspicious of British staples such as sausage, bacon and egg,' said a source.

The Chinese also objected to the idea of valets and maids entering the rooms of officials to turn down beds and unpack luggage, as is routine for state visits.

Palace insiders claim officials did not want the domestic staff seeing computer screens and other items of IT equipment they had installed inside so-called 'technology tents'. Whether these were for gathering intelligence is not clear.

Whatever the case, the Queen insisted that none of the 26-strong delegation could use laptops or tablets during the state banquet in honour of President Xi.

The other problem was that, late in the day, the Chinese tried to change the names of guests who had been allocated seats at the banquet, causing a security headache.

But then security had been a major sticking point for the whole visit. The Chinese wanted a bodyguard to travel in the horse-drawn carriage with the Queen and President Xi along the Mall. The Queen and Prince Philip never have protection officers in their carriages.

They were also anxious that demonstrators, such as those from the Free Tibet campaign, were kept out of view of the President, especially when he attended a banquet at the City's Guildhall.

It is clear that the state visit was a diplomatic nightmare for Buckingham Palace staff, who, in the end, managed to stave off most of the demands. As a royal source explained: 'We were walking on eggshells around the Chinese. They are notoriously difficult.'

But it also tested the security forces. Which is why, when the Queen was introduced to Lucy D'Orsi, the police officer who oversaw security for the visit, she said: 'Bad luck!'

The royal mingled with other guests including Pastor Kofi Banful and Jayne Banful in the garden of Buckingham Palace, as up to 8,000 guests attended the first royal garden party of the year

We still don't know why these comments were ever broadcast. Usually officials keep cameras at a discreet distance from the Queen, but Wilkinson has come to be seen as almost part of the royal entourage and has greater access.

The highly respected cameraman began working at the Palace after the death of Princess Diana, as an initiative to limit the number of TV crews following the Queen.

The arrangement has worked well and he is a popular and trusted figure at Buckingham Palace, where he has his own office.

He was armed on this occasion with his usual camera and a 'top mic' — a microphone meant to pick up only ambient sound.

As he has does routinely, Wilkinson sent the unedited film to the BBC, ITV and Sky, which jointly pay his salary. We understand he did not listen to the garden party clip before dispatching it, as he assumed it would have picked up only background noise.

As we now know, the exchange about China, broadcast by BBC News At Ten, sent diplomatic shock waves around the globe. Foreign Secretary Philip Hammond was forced to make a grovelling statement.

One senior royal source said: 'This is a major screw-up. I can't recall a Foreign Secretary ever having to intervene over something Her Majesty has ever said in public or private. She will be mortified.'

The Queen's comments come after David Cameron said he had 'fantastically corrupt countries' coming to London for key summit while chatting to the Queen and Archbishop of Canterbury at a Buckingham Palace event on Tuesday

It was claimed yesterday that the Queen's plastic umbrella may have acted to amplify her voice.

But a courtier was quick to dismiss this theory. 'There was no umbrella in sight when the Queen was talking to Cameron and the Archbishop, where their conversation was just as audible,' he said.

Yesterday some commentators suggested it suited the Queen for her remarks to be made public, due to unease at the eagerness with which the Government had been seen to be 'kowtowing' to the Chinese.

However, a royal source dismissed this: 'It's a travesty to suggest that. The idea that at the age of 90 the Queen is going to start indulging in diplomacy via the BBC is ludicrous.'