Diana's memory lingers over royal engagement

London, England (CNN) -- News of Britain's next royal wedding was on the front page of every British paper Wednesday, but so were mentions of the late Princess Diana.

The day after Prince William announced he had proposed to his longtime girlfriend, Kate Middleton, tabloids carried full-page pictures of the couple and broadsheets ran large, above-the-fold headlines.

"We got there in the end, darling!" was the headline on the Daily Mail. "(And it's sealed with Diana's ring!)"

"Something borrowed, something blue," wrote The Times, referring to the large sapphire-and-diamond ring William used to propose to Middleton last month.

"With this ring, Di thee wed," wrote the Daily Mirror.

William said in the couple's first joint interview Tuesday that he chose to use the ring because he wanted his mother to "be with us at such a happy time." Diana died in a Paris, France, car crash in 1997, when William was 15.

Attention on the ring and the link to Princess Diana showed how much her memory is already hovering over the upcoming wedding.

"The presence of Diana, it has always been there throughout William and Harry's life, and it will now become even greater, because Kate is going to be compared at every turn," said Mark Saunders, the author of several books on the royals, also making reference to William's brother and Diana's youngest son. His remarks were made on CNN's "The Situation Room." "We're supposed to call her Catherine now -- Catherine will be compared to Diana constantly. It will never go away."

Richard Fitzwilliams, a public relations consultant and royal commentator, said the comparisons with Diana can only go so far.

"I assure you that Kate Middleton is not being looked at as another Princess Diana," he told CNN. "I think Prince William was emphasizing in the interview it's time to move on."

British Prime Minister David Cameron passed on the congratulations of the whole House of Commons during his weekly question time on Wednesday.

"This is wonderful news," he said. "We look forward to the wedding itself with excitement and anticipation."

That same sentiment will also draw huge numbers of tourists to Britain over the next few years and boost the British economy by 620 million pounds ($985 million), a retail research firm said Wednesday.

Wedding-related merchandise sales alone could top 26 million pounds ($41.3 million), according to Neil Saunders, a consulting director at Verdict. Food and grocery retailers could also benefit as people buy extra food, treats, champagne, and wine to celebrate the occasion, he said.

Tourism and travel could bring in an additional 216 million pounds ($343 million), he said.

"Although times have changed since the last big royal engagement of Prince Charles and Lady Diana, many people will still be keen to buy some form or keepsake or memento and retailers will rush to capitalize on the merchandising opportunities," Saunders said.