A BBC Panorama investigation revealed there was confusion over whether the heir to the throne’s ceremony at Windsor Castle on April 8 would be permitted under current legislation.
The 1836 Marriage Act allowed for civil marriages in England for the first time, with the exemption of the royal family.
Legal experts interviewed by Panorama argued that this was updated in 1949 but that no specific changes were made to the royal exemption. A Clarence House spokesman said: “Legal advice was taken from four different sources and all agreed that it is legal for a member of the royal family to marry in a civil ceremony in England.”
Constitutional expert and friend of the prince, Lord St John of Fawsley, branded the programme “an absolute disgrace.”
“It’s nonsense and nonsense on stilts. The purpose of the explanation in the act was to safeguard the royal family from the side effects such as the bans,” he said.
“It was never intended to ban civil marriages as such.
“The palace has taken legal advice from the highest authority. The Lord Chancellor has been consulted. Government ministers have been consulted. The marriage is valid and Camilla would be queen.”
Questioned on whether Ms Parker Bowles would still adopt the title HRH Princess Consort instead of queen when Charles becomes king, he said: “She may use it. Things will have changed by then.
“It’s not what people are called. The people realise that the prince needs the support of a devoted and intelligent woman.”
Aides to the prince have said legislation could be introduced in the future to “tidy up” the matter of the future title of Ms Parker Bowles.
In the BBC1 documentary, Dr Stephen Cretney QC, Emeritus Fellow of Legal History, Oxford University, said he found it impossible to understand how a civil marriage for the couple could be legal.
He said: “There is no statutory procedure whereby members of the royal family can marry in a register office. Although there may be this ceremony and public rejoicing, it could be the Prince of Wales is not married and Ms Parker Bowles is not his wife.
Constitutionally it’s important to know whether they are married or not.”
According to the programme, the government and Buckingham Palace have taken advice from several independent lawyers who have advised the marriage would be legal.
Clarence House told the programme it believed the 1949 Act was not a continuation of the first Act but a completely new one which did not specifically prevent members of the royal family from having civil marriages. However, Valentine Le Grice QC said: “I am unsure of any such legislation.
“It’s not open to them to follow the normal procedures of registry marriage.”
The legal experts say until recently the government’s stance had been that under the act a civil marriage in the royal family in England was not allowed.
They are now calling for recent legal advice to the Government to be published to clarify the shift.