Some of the above feedback is way too conservative.

Yesterday I arrived into HKG on BA27 at 16.55. Out of the plane at 17.10. I comfortably made UO32 (HK Express) at 17.55 to Haneda. This was a separate booking that required passport check at the UO desk inside the transit area.

Granted I was HBO, but it is not a difficult airport to get through.

On a side note, come on England!