The scientists at Aldermaston disclosed yesterday that they had matched the Duke's blood sample with the remains of bodies believed to be those of the Tsarina and her children, using DNA techniques.
The tests were undertaken after nine skeletons were unearthed in a pit in Ekaterinburg in eastern Russia in July last year. They were believed to include the remains of Tsar Nicholas II, his wife the Tsarina Alexandra, and three of their five children. They were allegedly executed by the Bolsheviks in 1918.
Moves to grant the family asylum in Britain in 1917 after the February revolution were blocked by George V.
The remains were brought to Britain for forensic examination by Dr Pavel Ivanov, one of Russia's leading DNA scientists. The Duke of Edinburgh is related to the Tsarina through his mother and his grandmother, the Tsarina's sister.
The Home Office said yesterday the DNA analysis confirmed that there was one family group among the bones and that the sexes of the various bodies were consistent with the tentative identification made in Russia.
The Duke of Edinburgh's positive match was the first step. The next stage will be to match the DNA extracted from the bones with samples provided by known relatives of the Tsar and Tsarina. Tests on the Tsar's side of the family have proved inconclusive.
The Home Office expects definite identification early next spring. The scientists are using the technique of polymerase chain reaction.
It amplifies DNA into large enough amounts for genetic fingerprinting, which analyses the variation in the chemical structure of the DNA between individuals.
Because of the age and condition of the bones, mitochondrial DNA is being used for analysis. This is maternally inherited.
'If validated, the techniques used will be applied to criminal casework and will extend the wide range of services we provide,' Dr Janet Thompson, director general of the Home Office Forensic Science Service, said.
The case of the Russian royal family may help the service, which was turned into a semi-privatised agency last year, to overcome the blow to its credibility caused by a succession of high-profile successful appeals over faulty forensic science evidence, including those by the Birmingham Six and the Guildford Four.