Princess Diana enjoyed upstaging her Prince Charles during engagements

A royal insider has revealed how Princess Diana resorted to public tactics to take revenge on Prince Charles at the height of their unhappy marriage.

Veteran royal photographer Ken Lennox, who captured the first ever picture of Charles and the late Diana together when their courtship started, witnessed how their relationship fell apart over the years.

Speaking on ITV’s Inside the Crown: Secrets of the Royals, which airs at 9pm tonight, he said the moment their relationship began crumbling was during their royal engagement in Australia in March 1983, when she burst into tears outside Sydney Opera House – and was ignored by Charles.

Ken said a press officer at the time told him it was due to ‘jet lag and heat’, however her former press secretary Patrick Jephson soon noted how Diana appeared to purposefully ‘laugh a lot’ during joint engagements with Charles – not ‘because she was having fun, but to annoy her husband’. 

Speaking about being just feet away from her when he captured the moment she broke down in tears, Kensaid: ‘Diana burst into tears and wept for a couple of minutes.’

The press officer told Ken it was jet lag and heat, but Ken said: ‘I don’t  think Charles noticed. If he had it was typical of him to look the other way.

‘That was the first sign something was wrong and we then began to see other things happening.’

He added: ‘I couldn’t give away a picture of the royal family before Diana came along. When Diana came along all that exploded’. 

Meanwhile Patrick Jephson, former press secretary to Diana, said: ‘As professional royal performers they were unbeatable, but behind the scenes it was quite different. They didn’t talk to each other, there was minimal eye contact, they were short tempered with each other.

‘Diana enjoyed upstaging her husband and if she was laughing and smiling more it wasn’t that she was having more fun but that she knew it got on his nerves’. 

Diana’s former press secretary Patrick Jephson soon noted how Diana appeared to purposefully ‘laugh a lot’ during joint engagements with Charles – not ‘because she was having fun, but to annoy her husband’

Comparing royal marriages over the decades, historian Sarah Gristwood noted: ‘In a way Charles and Diana’s marriage was the last royal marriage played out by old royal rules, that he had to find a suitable bride – a young aristocratic virgin bride.’

And recalling the beginning of their arranged romance, royal author Penny Junor added: ‘It was the most curious engagement as they didn’t know one another, Diana was taken out of a flat she shared with girls and given a suite of rooms at Buckingham Palace.

‘But the perfect girl Charles thought he was falling in love with was much darker and more moody, and by the time they walked up the aisle the relationship was in a very bad way.

‘Charles always said he would marry with his head not his heart and I think that was a hangover learnt from Prince Edward’s abdication’. 

She added: ‘I really believe that William and Harry have learned a lot of lessons watching their parent’s marriage.

‘Diana told William and Harry to marry for love, and to their great credit both of them have married for love.’

Veteran royal photographer Ken Lennox, who captured the first ever picture of Charles and the late Diana together when their courtship started, witnessed how their relationship fell apart over the years

Meanwhile Prince Charles’ goddaughter India Hicks, who was a bridesmaid at their wedding, remembered: ‘It was an extraordinary experience for a 13-year-old child.’

Talking about the dress fittings, she said: ‘There was a feeling of fun about it, we would be on the floor above, she would be on the floor below. 

‘What I do remember is as the weeks went by Diana became thinner and thinner and thinner, and they had to take the dress in and in and in, and so there was a lot of scurrying around to make sure that dress was fitting her.

‘Looking back she was just 19, just a child herself, but as a 13-year-old I was quite impressed by her. 

‘On the day, as she stepped out of the carriage her 25ft veil began to unfold and we realise it was a horror story – just 25ft of crumpled mess.’

She added: ‘I was so excited about my first ball that evening, and after the wedding I went home and lay down for a moment, then woke up later to find my whole family had gone to the ball and left me behind. I was livid!’.  

Meanwhile Prince Charles’ goddaughter India Hicks, who was a bridesmaid at their wedding, said: ‘What I do remember is as the weeks went by Diana became thinner and thinner and thinner, and they had to take the dress in and in and in, and so there was a lot of scurrying around to make sure that dress was fitting her.’