EVERYBODY is allowed one or two gaffes now and then. Princess Anne, generally the most sensible, decent and hard-working of her family, did put her foot in it when she seemed to suggest recently that people who lived on their own were selfish.

It was in the context of an interview to promote just one of her many good causes, The Mission to Seafarers.

"Life in general nowadays is more and more isolating," she said. "Most people would call it independence, but I'm not sure what that means. It could mean just plain selfish. It could be more convenient just to live all by yourself, but if it means that you don't understand the impact of your life on other people's lives, and how you depend on other people all the time, it's no good."

Look at her words closely and you get the sense of a thoughtful woman struggling to articulate her feeling that our increasingly fragmented society, with its broken families and emphasis on self and image at the expense of family values, has somehow lost the plot.

There may even be a grain of truth in that. But it is easy to understand why her words could be hurtful to those she never intended to hurt: mothers struggling to bring up children in the aftermath of a painful divorce, say, or elderly people living alone after the death of a much-loved spouse.

The Princess's gaffe is yet another example of how, for even the most well-intentioned of Royals, perhaps the bestpolicy is just to keep quiet.

By-and-large, the princess has managed to follow successfully such a policy throughout her 50 years. Just contrast the lack of fuss being made about her 50th birthday today with that made over the 100th birthday eleven days ago of her grandmother.

There is to be no official celebration. That, apparently, took place in June in a party held at Windsor Castle for a clutch of royal birthdays, including the Queen Mother's 100th, Princess Margaret's 70th and Prince William's 18th - though how many people realised at the time that Anne's 50th birthday was being celebrated too? Instead, she is expected to mark her birthday today privately with her family.

The same lack of fuss has attended just about everything she has done. Imagine the frenzy that would surround Prince William if he were selected to represent his country in the 800 metres at this year's Olympic Games. Anne did represent her country at three-day-eventing in the 1976 Montreal Olympics.

Just a few years earlier, in 1971, she was named BBC Sports Personality of the Year as well as the Sports Writers' Association's Sportswoman of the Year after winning the individual championship at Burghley on the Queen's horse Doublet. Despite the recognition she achieved, though, there was none of the hysteria bordering on idolatry that might have been expected had she been a less self-effacing Royal.

Even the break-up of her first marriage, to Captain Mark Phillips, was attended by none of the fuss that accompanied the spectacular and very public collapse of the marriages of those more 'celebrated' royals, Charles and Diana, Andy and Fergie.

The split might have been prompted by 'personal letters' to Anne from the Queen's equerry, Commander Timothy Laurence, stolen from the Princess Royal's briefcase and sent to The Sun newspaper.

But somehow the mud didn't stick. There was none of the public airing of grievances that accompanied later royal divorces. In Anne's case, the overriding impression was that of a dignified and decent woman struggling hard to cope with the pain of ending a marriage which just hadn't worked out. There can be few who begrudged her the personal happiness she seems to have obtained following her marriage to Commander, now Commodore, Laurence.

Anne Elizabeth Alice Louise was born at Clarence House on August 15, 1950, second child of Princess Elizabeth and the Duke of Edinburgh.

Just 18 months later, her mother became Queen and the family moved to Buckingham Palace.

She was taught at home in a small class by governess Catherine Peebles before going to Benenden School, Kent, at the age of 13, the first Sovereign's daughter to attend boarding school.

She left five years later, with six O-levels and two A-levels. Instead of going to university she entered the public life of the Royal Family. And so began a career of quiet good works.

As is so often the case, it's the quiet ones who make least fuss who do all the hard work. Anne has long been recognised as the busiest, as well as probably the quietest, member of the Royal Family.

Royal detractors may insist that's not saying very much. But the fact remains that in 1998 alone she carried out 679 official engagements. That's just about two for every single day of the year.

Already this year she's been a regular visitor to North Yorkshire - always, of course, in her usual low-key sort of way.

Last month she was in York to see Army officer cadets being put through their paces at Strensall barracks. In May she visited a conference hosted in Harrogate by the Intensive Care Society - and she'd already been in York the month before to visit York University's biology department.

And then there are her 'causes'. She is associated with more than 200 organisations and has been a tireless worker for charity - president of Save the Children, patron of the above-mentioned Intensive Care Society and of the Royal College of Paediatrics among many others, instigator of the Princess Royal Trust for Carers, which works tirelessly on behalf of a group of selfless people whose needs are largely ignored by society as a whole.

So it's little surprise that Anne should be the royal who gave most support to the York-based campaign for a memorial to the women of the Second World War. The Queen and Prince Charles both gave their backing, too: but it was Anne who acted as the campaign's vice-patron.

Major David Robertson, chairman and trustee of the campaign launched at Imphal Barracks, said the princess's involvement had been enormously important - all the more so because she was such a widely respected and well-liked member of the Royal Family.

"Over the last ten years Her Royal Highness has been closely involved with women's issues," he said. "She is one of the most respected members of the Royal Family and we were delighted to get the support of someone of her standing.

"We certainly wish her a very happy and prosperous birthday."

Few would disagree with that.