Knock knock! Who's there?

I was woken at 4am by knocking and scratching at the bedroom window.  (The bedroom is on the ground floor with French windows.)  I could also hear a magpie alarm call so assumed at first that it was a magpie.  The noise persisted so I got up to look and there was the culprit.

I only managed a few blurry shots with the first camera I could find and I hadn't even had time to put on my glasses.  I presume the cub was attracted by its reflection in the window.  It is interesting that it could get into the walled garden as the only access is over a 4 foot high wall.  I hope this doesn't become a habit.