Margaret's 'illegitimate son' takes his case to the High Court

An accountant from Jersey who claims to be the illegitimate child of Princess Margaret is to go to court next week to try to prove he is 12th in line to the throne.

In a highly unusual case with wide implications for Britain's constitution, a judge is to be asked to rule on the rights of illegitimate children to the royal succession.

Robert Brown, from St Lawrence, will also use the Human Rights Act to challenge the rules that bar public inspection of the "sealed" wills of Princess Margaret and the Queen Mother.

Mr Brown, 51, who was born in Kenya, says he has been forced to take his case to court because Buckingham Palace has refused to confirm or deny his claim to royal title by accepting his offer of a DNA test, which would conclusively settle the issue. If he wins his claim it is possible that he will be entitled to tens of millions of pounds in inheritance.

A summons issued by the High Court requests executors of the wills of the Queen Mother and Princess Margaret to attend a hearing on Tuesday in front of Senior District Judge Philip Waller. The judge will consider directions on whether the case should continue.

The Queen's solicitors, Farrer & Co, have been instructed to represent the executors of the wills; lawyers for the Attorney General, Lord Goldsmith, will also be in court.

Mr Brown says all he wishes to do is to establish the truth about his parentage and any rights he may have under the constitution.

At the heart of his claim is a meeting he had with a woman he believes to have been Princess Margaret when he was a young boy in Nairobi.

"I don't recall ever seeing her before but I know this woman spent some time with me. I remember we were playing games and during the day she told me that I must be on my very best behaviour because one day I might be king of England. That meeting has stayed with me and kept me going. Although I don't think I ever saw her again."

Mr Brown realises that to many people his assertion may seem ridiculous and he says that for a long time he did not want to pursue his claim.

"But I am driven by memories and inconsistencies that seem to lead to this one possible conclusion," says Mr Brown.

So far the documentary evidence supporting his claim has been equivocal, neither proving his claim nor ruling out the possibility that he could be the illegitimate son of Princess Margaret. Robert Brown was born was born on 5 January 1955, in Nairobi although his birth was not registered until 2 February and the certificate recording it is dated much later, 4 June of the same year.

His natural mother is named as Cynthia Joan Brown (née Lyle), a society model working for Hardy Amies, the Queen's former official dressmaker, and his father was Douglas Richard Brown, who had been posted to Kenya with the Army during the Second World War. One theory is that, to avoid a public scandal, the couple agreed to adopt a baby born to Princess Margaret.

But questions have arisen as to how feasible it would have been for the Queen's sister to hide her pregnancy while she continued to keep public engagements. "All I can say is that the pictures of the Princess during 1954 are inconsistent. Certainly in May of that year there are pictures of Princess Margaret where you could put your hand around her waist but throughout the year the dresses are getting bigger," Mr Brown said.

A key part of his case is that at the time of his birth, the Princess is described in at least one report of the day as been confined to bed with a "hacking cough".

Mr Brown has been unable to find any record of Princess Margaret visiting Kenya in the year of his birth but the following year she chose the country as the destination for a royal tour.

It is during this visit, between 19 and 25 October 1956, that Mr Brown believes he met his real mother. "I have asked to see the official records relating to Princess Margaret at that time but have been told that they are closed." Mr Brown's suspicions were further aroused when his own investigations uncovered his legal parents' marriage certificate, which had been registered in Nairobi. "It was the only one I saw which didn't have a signature from the registrar and looked like it had been placed or stuck on top of another certificate."

On many occasions during his childhood and later adult life he says his mother made oblique references which in hindsight Mr Brown says hint at his royal connections.

"In the sense of being a mystery woman, Cynthia was certainly very private. I had no idea as to her 'past' when Cynthia was alive. It was never mentioned or discussed. Cynthia was a woman of great quality and quiet bravery. If Cynthia did have any absolute idea or even inkling it must have been a significant burden for her - an impossible situation almost."

Mr Brown is still unclear who his natural father might be. But two possibilities are Group Captain Townsend, the former RAF fighter pilot who had an ill-fated romance with Princess Margaret, and Robin Douglas-Home, with whom she had a well-publicised affair in the 1960s.

A spokeswoman for Buckingham Palace said: "While there is a court case pending we can't comment on this matter."