United Kingdom, June 4 -- A man has been arrested for allegedly trespassing in the grounds of Windsor Castle.

The Metropolitan Police and Thames Valley Police have both launched investigations after the intruder was found on the grounds of the royal residence over the weekend.

A Metropolitan Police spokesperson said in a statement: "A man in his 30s has been arrested on suspicion of trespass on a protected site and possession of Class A drugs after entering restricted grounds at Windsor Castle.

"Officers in the grounds spotted the man just after 13.00hrs on Sunday, 1 June and quickly arrested him.

"He was then passed into the custody of Thames Valley Police."

It's been confirmed that the man was "quickly challenged by Met police offi...