Blackstone and the Golden Egg (Inspector Blackstone)

Rivalling Anne Perry, the third in the Victorian series by the author of the much-loved Sally Spencer DCI Woodend books
The theft of the fabulous Fabergi golden egg from a Russian country estate goes far beyond the bounds of mere robbery. The victim is the Prince of Wales, the egg itself a gift from the Russian Tsar and if the Tsar takes offence at the Prince's carelessness in losing it, the delicate balance of power in Europe could be destroyed for ever.
Yet if Blackstone is investigating a simple robbery, why is there an attempt on his life the moment he sets foot in Russia an attempt which would have succeeded but for the intervention of mysterious masked figure? Why will no one talk about the closed coach which fled the scene after the theft? And what is the motive behind the murder of a young British officer staying at the house?
The more Blackstone learns, the less he knows but the surer he is that the robbery is merely masking a much deeper, darker, secret!