Two men have been arrested by police after a break-in at Buckingham Palace earlier in the week.
It's one of the most serious security breaches at the Queen's London residence in 30 years.
Former Protection Officer for Princess Diana, Ken Wharf:
(SOUNDBITE) (English) ROYAL SECURITY EXPERT, FORMER PROTECTION OFFICER TO PRINCESS DIANA, KEN WHARF, SAYING:
"It does happen and it will happen again simply because you cannot give anything 100 percent security when you allow access so close by the general public which... And this is a global tourist spot, one of the most visited places in the world."
Some visitors found the incident worrying.
SOUNDBITE (English) VISITORS SAYING:
"When you just go to visit they haven't... they have so many security procedures there already, so for someone to get in when it's closed and there's meant to be a lot of security stuff going on, it is quite scary, because you think, where else could they have got into ? Especia
