The combination of sex, money and lavish costumes has proved a winner in the past for the makers of royal sagas. But can the Queen Mother's story revive interest in the House of Windsor?

The ingredients outclassed anything a glossy American soap could muster. The sets were grand, the costumes were glittering, and the characters were wrung through an emotional mangle of love, hate and deception.

But this wasn't Joan Collins's Alexis rubbing shoulder pads and exchanging catty comments with Linda Evans's Krystle in Dynasty. This was real life. Or as real as the continuing saga known as The Royal Family ever gets.

In the old days, the makers of Diana: Her True Story, a 1993 mini-series based on Andrew Morton's tell-tale bestseller about the Princess of Wales's troubled life, would probably have been sent to the Tower. It was a rare example of television refusing to curtsey to the unwritten law that says TV drama about royals, especially those still alive, should not stray too far from the truth.

The £2m production was recognised for what it was - high class tosh cashing in on the royal crisis. True or false, it didn't matter as long as the result was superior soap.

The planned film about Prince William, in which Lulu's actor son Jordan Frieda will play the royal heir, seems likely to be equally controversial and equally soapy.

The story opens with the 1997 crash in Paris which killed William's mother Diana, Princess of Wales. Little wonder the project has already drawn criticism from both Prince Charles and Diana's mother, Frances Shand Kydd.

Frieda, 24, has already admitted on a US TV show that the film may provoke criticism. "Well, hopefully, there'll be a little bit. I mean, you'd be disappointed if there was no response. But I think it will be well taken, knowing what we're going to do," he said.

There are fewer worries about Bertie And Elizabeth, a two-hour ITV blockbuster about the marriage of Queen Elizabeth the Queen Mother and George VI. It may not have the seal of royal approval but the makers seem intent on celebrating the Queen Mother's life rather than a gritty drama-documentary expose.

Neither can anyone be accused of cashing in on the Queen Mother's death. Production on the Carlton film was completed well before she died in March. Only a slight revision in the closing caption over the final scene was needed to take account of her death.

The drama sets their married life together against the backdrop of major national and world events, including the abdication of George's elder brother and the Second World War.

Episodes from the Queen Mother's life recreated for the cameras include her visit with the King to the East End of London after German bombs fell on Buckingham Palace, and their 1939 trip to the US.

James Wilby and Juliet Aubrey play the royal couple, with Alan Bates as George V and Eileen Atkins as Queen Mary.

The 7th Marquess of Bath's stately home, Longleat House in Wiltshire, stands in for Buckingham Palace, as well as scenes at Balmoral and Sandringham.

Aubrey regrets that the Queen Mother died before the film was screened. "I wanted her to be alive when it went out, just on the off-chance that she had nothing on that evening, watched it and liked it. I'd have been fascinated to know what she thought," says the actress, who plays her from the age of 20 to 52.

Bertie And Elizabeth brings the royal family history a little more up to date. Perhaps this and the Golden Jubilee will revive TV's interest in such tales. The BBC realised the value of the monarchy when The Six Wives Of Henry VIII was shown in 1970. The mix of sex, violence and lavish costumes attracted record audiences on BBC2 and the series was sold to over 75 countries.

It led, the following year, to Elizabeth R in which Glenda Jackson played the Virgin Queen. The series won five Emmy awards in the US.

Not wanting to be left out, ITV gave viewers Edward The Seventh in 1975. Annette Crosbie, long before she became Victor Meldrew's wife in One Foot In The Grave, won a Bafta for her performance of Queen Victoria. Robert Hardy was her Prince Albert and Timothy West starred as Edward VII.

This series had something others lacked - the present Queen's permission to film scenes in Osborne House, Sandringham and other royal properties.

Francesca Annis, who played the Prince of Wales's lady friend in Edward The Seventh continued the role in Lillie, three years later. This was more concerned with her than the Prince, relating her rags-to-riches story from humble beginnings to a glamorous royal mistress.

Another royal liaison was at the heart of Edward And Mrs Simpson, ITV's lavish seven-parter about events leading up to the abdication crisis. Edward Fox played his namesake Edward with Cynthia Harris as American divorcee Wallis Simpson. She was portrayed as a calculating schemer, something that didn't go down well with the real duchess, living in France.

There have been sightings of real royals too. Prince Charles made a guest appearance in Coronation Street during its 40th anniversary edition. He also narrated his own story on Jackanory. Princess Anne went on safari with Valerie Singleton in Blue Peter. Prince Edward led the fun and games in a much-criticised royal edition of It's A Knockout, as well as presenting documentaries.

Their mother has yet to apply for membership of Equity the actors' union. She leaves that to lookalikes, although Tesco TV ads star Prunella Scales did impersonate Her Majesty in a BBC version of Alan Bennett's stage play A Question Of Attribution.

* Bertie And Elizabeth is on ITV on June 4 at 8.30pm.