Prince William will do well to avoid the faux-pas made by the Prince of Wales after his own engagement.

When Prince Charles and Lady Diana Spencer were asked if they were in love, Prince Charles said: “I’m amazed that she has been brave enough to take me on and I suppose in love.”

His shy, giggling bride-to-be added “Of course”, before the Prince remarked: “Yes, whatever in love means.”

Prince Charles’s nitpicking answer was to come back to haunt him when their marriage ended.

The engagement was an-nounced at 11 a.m. on February 24, 1981 by Buckingham Palace. The couple were pictured on the same day in the grounds of the royal residence – Diana, just 19, wearing her engagement ring – a large sapphire encircled with diamonds

In interviews to mark their forthcoming nuptials, Prince Charles, who was 32 at the time, and Diana walked arm in arm across the Palace lawn.

Wearing a bright blue jacket, matching skirt and white blouse complete with a bow neck tie, Daina said she was “delighted and thrilled, blissfully happy”, adding “With Prince Charles beside me I cannot go wrong.”

Tributes to the couple were made in both Houses of Parliament. Five months later they were wed.