A right royal security scare unfolded in Britain this weekend over a missing USB stick.

The thumb drive contained details of the exact route the Queen takes to Heathrow Airport.

It's said to also contain information about the identity needed to get into restricted areas, patrols and security for the Queen, and measures to guard against terrorists.

The memory stick was eventually found by an unemployed man in London.

UK correspondent Gavin Grey said it's being taken very seriously.

"It really is a mass of information. A Heathrow spokesman said 'we've reviewed all our security pans and our confident that Heathrow remains secure. They have launched an investigation'."