A royal author has claimed that Tony Blair's former press secretary Alastair Campbell was left 'instantly smitten' after he met Princess Diana for the first time.   

The Princess of Wales met Campbell on the evening of the 1995 local elections after she had enjoyed a meal with Tony and Cherie Blair.

Valentine Low recalls the surprising interaction in his new book - which explores the relationship between the monarch and the Prime Minister - titled Power and the Palace.

According to Low, Blair and his wife Cherie were dining with the Princess of Wales in Hyde Park Gardens when Campbell arrived to take Blair back to Labour headquarters. 

During this meeting that Diana praised Campbell claiming she wished she had a press officer as talented.

Low wrote: 'After ringing the bell to let them know he was there, he was waiting in the car when Blair tapped on the window.

'"Someone wants to meet you," he said. That someone was Diana.'

He continued: 'They stood there flirting for a few minutes, while Blair and Cherie looked impatient. But Campbell, as he put it, was "lost in the beauty".' 

Their brief conversation left a big impression on Campbell who waxed lyrical about the princess in his diary.

According to Low, 'Campbell was instantly smitten' and went on to describe Diana in his diary as 'absolutely, spellbindingly, drop-dead gorgeous.'

Campbell's new found love for the Princess of Wales did not go unnoticed by his colleagues.

Blair's chief of staff - Jonathan Powell - said that Di had got Campbell 'a bit besotted'.

Low added: 'Another senior Labour figure from the time said: 'It was ridiculous. He was like a dog with a bone, saying "I think she really fancies me," Really? I thought, "She knows what she is doing.'

In January 1997, Diana joined Blair and Cherie alongside Campbell and his partner, Fiona, for a dinner in Hackney.

Low claims that the atmosphere at the meal was 'a little awkward at first' and Blair was 'unable to decide whether to flirt with Diana or treat her like a visiting dignitary'. 

He continued: 'Blair was "jumpy", worried that news of the dinner would get out - and not entirely happy that Campbell was there.

'Blair dropped heavy hints about Diana having a more developed role in public life. Diana, however, didn't bite at all.'

At the end of the night the love struck Campbell had one last encounter with the princess. 

'When they left, Cherie kissed Diana on both cheeks. What was Campbell going to do, wondered Diana,

'He shook her hand, and she giggled. "I love her laugh", he wrote. He was still besotted,' Low said.

According to Low, Blair at this point was not so captivated by the princess.   

'He [Blair] saw Diana's potential but also viewed her as "very manipulative and determined".'

'In his memoirs he said she was "extraordinarily captivating" and had strong emotional intelligence as well as being "very capable of analytical understanding".

'But he was cautious: "I really liked her and, of course, was as a big a sucker for a beautiful princess as the next man: but I was wary too".'

Low added that once Campbell and Blair were inside No 10, following their landslide victory in the 1997 election, they 'grew a touch more cynical' about Diana. 

But both men would have little time to work with or alongside the princess due to her sudden and tragic death in August that year.

In his tribute to Diana, Blair famously described her as the 'people's princess'.

The endearing description was coined with the help of Campbell who helped write a speech for Blair on the back of an envelope.

Since then, the 'people's princess' has become synonymous with Princess Diana and with the popular memory of the outpouring of grief that following her death.

Adding further to the enduring legacy of the Princess of Wales.