The Queen was said to be 'horrified' after a plague of rats and mice were found running around the kitchen area of Buckingham Palace.
Staff at the royal residence have reportedly called in a pest control team to tackle the rodent problem.
The infestation is becoming a problem in the capital city, especially in very old buildings like the Palace, which dates back to 1703.
A source told The Sun: "Rats have been spotted around the outside of the kitchen areas which clearly isn't ideal.
"Staff in the lower quarters especially have become quite used to seeing little brown mice tearing along the corridors.
"There isn't a huge amount that can be done. But council pest control did come in to put down poison and examine the vermin problem."
It is reported that officials have given staff, in particular kitchen workers, basic training such as shutting cupboard doors and sweeping away bits of food in order to stop the problem spreading.
Last year, Britain was under threat from a 'super-rat invasion' due to a new generation of mutant rodents.
The vermin developed a genetic mutation known as L120Q, which renders many toxins useless, stated the newspaper.
A spokesperson for the British Pest Control Association admitted that the long-tailed rodents had grown increasingly immune to the poison.
