A huge number of the Queen’s staff are inviting people they meet on hookup apps back to royal residences, it has been warned.

Over 800 of the Queen’s staff have live-in quarters at St James’s Palace and the Royal Mews, where they are permitted to sign in guests.

However, police are said to be “deeply concerned” at the number of unvetted guests that the Queen’s live-in staff are allowing to stay overnight in the royal residences, with the numbers reportedly sky-rocketing following the advent of hookup apps such as Grindr and Tinder.

Chief Superintendent Dai Davies, the former head of royal protection, told the Mail: “Historically this has always been a problem, even when I was in charge way before the introduction of these so-called dating apps.

“If members of staff lived in certain quarters such as the Royal Mews and Kensington Palace, which have both single sex and married quarters, they were, and I presume still are, permitted to bring back unvetted guests.

“Often these guests were total strangers. It makes a complete mockery of the security structure, unfortunately.”

A source added: “There are real and serious security concerns at Buckingham Palace about members of staff use of dating apps such as Tinder.

“The palace police are particularly unhappy about the number of guests of servants staying overnight, especially when they may have only just met on Tinder.

“It is a security nightmare, especially in the current climate. The guests are allowed to stay at St James’s Palace but some have complained that when they leave they get asked ‘a million questions’ by officers. Police say they are only doing their job.”