One of the Queen's corgis has been put down after being savaged by an English bull terrier owned by Princess Anne.
One of Princess Anne's dogs bit two children last year
The attack is thought to have happened on Monday, when the corgis ran out to greet the Princess Royal as she arrived at Sandringham for Christmas.
Princess Anne was convicted under the Dangerous Dogs Act last year after the same dog attacked two children.
BBC royal correspondent Nicholas Witchell said the future of the dog, called Dotty, is now being reviewed.
Oldest and dearest
The Queen is said to be devastated by the death of her corgi.
It is thought it was Pharos, one of her oldest and dearest pets.
Corgis are famously associated with the Queen
Although Buckingham Palace is not saying anything about the incident formally, the Queen is reported to have joined her daughter and royal footmen in trying to separate the dogs.
But Pharos had been badly injured and had to be put down yesterday.
The Queen's love for her corgis is well known and they were last seen in public milling around the feet of England's World Cup rugby stars at a Buckingham Palace reception earlier this month.
Princess Anne appeared before magistrates last November and pleaded guilty to a charge that one of her dogs attacked two children in Windsor Great Park.
In that attack Dotty left a 12-year-old boy with a bite on the collarbone and two bites to the left leg.
Princess Anne told a court the dog was good natured
A seven-year-old boy was left with scratch marks on a leg, his back and an arm.
Anne was fined £500 and ordered to pay £500 compensation to the children and £148 in court costs.
She was told to organise training for Dotty, to keep her on a lead in public places and that the dog could be put down if there were similar attacks.
The children's parents were angry that the princess escaped with a fine and Dotty was not put down.
They said: "We do not think justice has been done. The dog is still free and is a danger to society."
The penalties for the offence can include a £5,000 fine, six months imprisonment and the animal being destroyed.
The princess' defence said Dotty was a good natured dog "lacking in malice".