According to various locksmith forums, recent years have shown a marked increase in the amount of people becoming locked out of their homes. Particularly those in new builds or homes that have been fitted with a UPVC door.

In line with new building regulations most new door installations use a facility on the Multipoint locking door mechanism known as split-spindle.

A split spindle system separates the inner and outer door handle. This means that, if you close the door from the outside; you will not be able to open the door using the outer door handle, unless you have a key. However, if you have left a key inserted in the lock on the inside of the door; you will be unable to open the door from the outside with another key.

A solution to this problem is to fit a Double Function Cylinder. These locks use a unique pick up cam which will allow the key to fully operate the cylinder even if another key is inserted on the internal side of the door. This also works, even if that internally located key is in the locked position.