Yes
If you leave a door unlocked, or leave a key in the lock, the bailiff may enter by turning the key.[1]
A bailiff cannot put his hand in a hole (e.g. a cat flap or letterbox) in order to pull back a bar or fastening to open the door or window because this amounts to burglary and trespass.[1]
The use of a landlord's key to gain entry is unlawful.[2]
If you leave the key outside, or under the doormat, which is found, but is not in the lock, entry would be unlawful.[3]
Improper use of keys to gain entry is illegal.[4]
Make sure your home is secure, but in certain circumstances, bailiffs may enter using reasonable force.[5]
[1] Ryan v Shilcock [1851] 7 Exch 72
[2] Miller v Curry [1893]
[3] Welch v Krakovsky [1919]
[4] Alford v Thrupp [1906] 67 EG 226
[5] See Bailiffs and entering using reasonable force.
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