A spokesman for Prime Minister Tony Blair ruled out an inquiry, saying nothing would be gained by repeating an investigation the French have already conducted.
"Everybody knows there has been an exhaustive investigation by the French authorities into the circumstances surrounding Diana's death and there will be nothing to be gained from repeating that here," he said on customary condition of anonymity.
She was killed, along with her boyfriend Dodi Fayed and driver Henri Paul in a car crash in Paris on Aug. 31, 1997.
A French judge has ruled that the driver's use of drugs and alcohol, and the car's high speed, caused the accident.
The spokesman said there eventually would be a coroner's inquest into Diana's death once French legal processes have been completed. An inquest also will be held into Fayed's death, although a date has not been set.
Dodi Fayed's father Mohammed al Fayed, who has never accepted that the crash was an accident, called for a public inquiry into the deaths.
On Monday, the Daily Mirror printed a letter it claimed was written by Diana to her butler Paul Burrell 10 months before her death, predicting that someone was planning "an accident in my car, brake failure and serious head injury in order to make the path clear" for Prince Charles to re-marry.
Neither Prince Charles' office nor a spokeswoman for Diana's brother, Earl Spencer, would comment on Burrell's claims.
The former butler stood trial last year for allegedly stealing hundreds of items from the princess's estate. The trial collapsed after the queen confirmed that Burrell had told her he was holding some of Diana's items for safekeeping.
On Tuesday, the Daily Mirror published more excerpts from Burrell's upcoming book "A Royal Duty." In one of them, Prince Philip reportedly told Princess Diana he "never dreamed" his son Prince Charles might leave her for Camilla Parker Bowles.
"I cannot imagine anyone in their right mind leaving you for Camilla," Philip wrote, according to Burrell's book.
In a series of letters, Burrell said, Philip expressed disapproval of both Diana and Charles for having affairs during their marriage and pointedly criticized Charles for his involvement with longtime companion Parker Bowles.
"We do not approve of either of you having lovers," Philip wrote in a letter in the summer of 1992, the newspaper said. "Charles was silly to risk everything with Camilla for a man in his position. We never dreamed he might feel like leaving you for her. Such a prospect never even entered our heads."
But Philip also told Diana that her behavior was partly responsible for strains in the marriage. She admitted having an affair with former cavalry officer James Hewitt.
"Can you honestly look into your heart and say that Charles's relationship with Camilla had nothing to do with your behavior towards him in your marriage?" Philip was quoted as saying.
The princess' apparently strained relationship with her in-laws has been widely discussed in Britain's tabloid press over the years.
Burrell, a longtime servant whom Diana once called "my rock," said the princess was distressed by some of the "accusing" letters that Philip, husband of Queen Elizabeth II, sent her in 1992 as her marriage was foundering. But later Diana "learned to respect his honesty," Burrell recounted.
Diana had gone public with her side of the troubled marriage by cooperating in the preparation of a book, "Diana — Her True Story."