Buckingham Palace trespasser is convicted murderer

"... Hennessy walked around the gardens for about 10 minutes toward the palace before being arrested."

"Police said he was not armed and claimed security measures had “worked effectively.”

Uh, no. 10 minuts does not equal effective.

The grounds of Buck's House are considerable at the rear but to my eyes almost impossible to get over-I would bet that he forced one of the doors?