There is an inherent weakness in all traditional inward opening timber doors.
The Kickstop range was devised by a family firm of locksmiths and security retailers in East London. Concerned about the growing trend for burglars to simply kick in a front or back door, they were all too aware that a door will split open along the grain much more easily after the door had been weakened as a result of morticing and lock fitting.
The strength or a good quality mortice lock is not in question but please remember, it's the door and frame that would split open and fail during a forced entry.
The main areas of weakness on an inward opening door are:
Kickstop has developed many products to deal with these security issues.