Norfolk - A colony of the endangered species is causing havoc at the royal residence after making new nesting arrangements in the Queen's ensuite composting lav.
The organic throne room is said to be completely infested after a Phobics Anonymous-sponsored rehoming exercise released thousands of extremely rare Great Graft spiders into fenlands surrounding the royal estate near the Norfolk Broads.
"It's just a bit of a lark, really," a London Zoo conservation satirist commented as news of the deadly arachnid infestation broke.
"Think of it as our contribution to the taxpayer-funded Queen's Austerity Diamond Jubilee."
The deadly arachnids were genetically modified to grow into 25cm-diameter hybrids in a breeding programme backed by the renowned genealogical guide to the British aristocracy Berk's Peerage.
Hundreds of the semi-aquatic creepy crawlies were originally brought up as vegetarians to deal with the menace of algal bloom clogging up British canals and waterways.
Unfortunately a laboratory accident involving nitrous oxide laughing gas turned a whole colony into deadly carnivores with a penchant for blood-blooded saggy-arse flesh.
Thousands of mutants are now on the loose forcing Queen Elizabeth to reconsider her annual Christmas plans to slum it as usual in the Sandringham pile.
Pest exterminators will be working round the clock to cull the colony before expected new generations see offspring grow to an expected 50cm in diameter.
A single venomous bite can reduce a 25lb corgi into a gibbering wreck.