The London Bar is a flat steel bar frame reinforcer with a D shape section to fit over the lock staple (keep) of a traditional rim nightlatch front door lock
If you're fitting a mortice lock, it's an unfortunate fact that this will result in a weakened door and frame that will split around the locks and hinges during a forced or 'kick-in' attack - unless extra measures are taken to strengthen the door
Kickstop products are designed specifically to reinforce and strengthen the door and frame around the existing locks and hinges. They don't require locking or bolting - once fitted, they automatically provide additional physical security and peace of mind every time the door is closed and locked. Because of this, they are recommended by the Metropolitan Police when advising on improved security