It was a disaster for Harry when he was rushed back to Britain after his Afghan tour of duty was leaked. But why was his first press conference suddenly cut short with a cutting motion across the throat?

Prince Harry has never shied away from saying how disappointed he was at having to leave front line military duties in Afghanistan and return to Britain.

In 2007, Harry, a skilled helicopter pilot, had been posted on tour of duty with the British media agreeing a strict ‘blackout’ on his presence in Afghanistan to help protect his safety.

After just four weeks, however, an obscure Australian magazine, New Idea, published the news on its website, writes royal author Robert Lacey – apparently with no knowledge of the blackout or the consequences of the breach.

But it was when the American investigative site, The Drudge Report, picked up the news a few weeks later and published on February 28, 2008, that the game was really up.

Harry sits with a group of Gurkha soldiers at an the observation post on JTAC Hill

Prince Harry sits  amid officers and men from the three services plus friends from his own regiment as he waits for his flight back to the United Kingdom, after serving ten weeks in Afghanistan before his cover was blown by the foreign press

Prince Harry steps off a plane as he returns from Afghanistan at RAF Brize Norton on March 1, 2008

‘When the news broke, Harry was in a remote base near the front line in Afghanistan,’ writes Lacey in his best-selling book Battle of Brothers. ‘He had to be helicoptered out and straight back to the main British base in the country, where he was put on an aeroplane to Britain.’

The news hit him hard, writes Lacey, who quotes Miguel Head, the Ministry of Defence Official who had been attempting to keep Harry’s whereabouts a secret. Head would later become chief of staff to the brothers.

‘He was very upset, actually,’ recounted Head. ‘He was really down. I wouldn’t describe him as angry – he’s far more mature than that… He was just very sad about it.’

Prince Harry had flown back along with three seriously wounded men – and this had been a sobering experience, writes Lacy.

The Prince was still wearing combat gear covered in sand when he landed and sat down for a press conference.

‘It was clear he was exhausted . he had not washed for a day and a half and he was obviously very upset as he tried to absorb the reality that, yet again, something he really cared about had been torn from him.

And after only two or three questions, there was a surprise intervention.

‘Prince William suddenly stood up at the back of the room. He had been seated behind Head, and as the ministry man turned to look, he saw the older prince making a cutting motion with his hand across his throat – saying, in effect, “this is over”.

Head’s explanation was simple.

‘It was simply a brother realising that at that point nothing was more important than his brother’s welfare…It says something about the closeness of the brothers and their authenticity as well.

Prince Harry, left, walks with his brother Prince William, right, shortly after returning from active duty in Afghanistan, at the Brize Norton air base in Oxfordshire

Both his father, Prince Charles, and brother, Prince William – just visible in the background – were at Brize Norton to meet Harry as he returned from active duty

Prince Harry leaves the press conference with his father and brother by his side

Prince William carried much of Prince Harry’s kit as they made their way towards the car

‘They will not fake who they are simply to play a game or go along with other people’s expectations.’

As for the Australian magazine that mistakenly broke the embargo, Head was charitable.

‘Poor old New Idea,’ he told Lacey. ‘This little-known, very friendly magazine came into the worst criticism – particularly in Australia, where the monarchy is very popular.

‘They had published the scoop of the century and just didn’t realise it.’