When it comes to securing your home or business, choosing the right lock is one of the most important decisions you can make. Two of the most popular options in the UK are mortice locks and deadbolts. While both provide excellent security, they work differently and suit different applications. This comprehensive comparison will help you understand which is best for your needs.
What Is a Mortice Lock?
A mortice lock is fitted into a recess (or "mortice") cut into the edge of a door. The lock body sits inside the door, making it far more resistant to forced entry than surface-mounted alternatives. Mortice locks are the standard choice for external doors in the UK and are required by most home insurance policies.
They come in various lever configurations — 2-lever, 3-lever, 5-lever, and 7-lever — with 5-lever mortice locks being the minimum recommended by insurers and police for external doors. Learn more about lever configurations here.
What Is a Deadbolt?
A deadbolt (also called a deadlock) is a locking mechanism that can only be operated by a key or thumb turn — it cannot be pushed back by applying pressure to the bolt. This makes it highly resistant to shimming and credit card attacks. Deadbolts are common in American-style security systems but are also widely used in the UK, particularly on UPVC doors.
Key Differences
Installation
Mortice locks require a professional to cut a recess into the door, making installation more complex. Deadbolts are typically surface-mounted or require only a simple bore hole, making them easier to retrofit.
Security Level
Both offer excellent security when properly installed. However, British Standard (BS3621) mortice locks are specifically tested and certified to meet UK insurance requirements. A 5-lever BS3621 mortice lock is generally considered the gold standard for UK external doors.
Door Compatibility
Mortice locks work best with solid timber doors. Deadbolts are more versatile and can be fitted to UPVC, composite, and timber doors. For UPVC doors, multipoint locking systems are often preferred over either option.
Insurance Requirements
Most UK home insurance policies specifically require a 5-lever mortice deadlock on external doors. A standard deadbolt alone may not satisfy your insurer's requirements — always check your policy documents.
Which Should You Choose?
For timber external doors: A 5-lever BS3621 mortice deadlock is the recommended choice and will satisfy most insurance requirements.
For UPVC doors: A multipoint locking system combined with a cylinder lock is typically the best option.
For internal doors: A 2 or 3-lever mortice lock or a simple deadbolt provides adequate security.
For additional security: Consider adding a deadbolt as a secondary lock alongside your existing mortice lock.
Professional Installation Matters
Regardless of which lock you choose, professional installation is crucial. An incorrectly fitted lock — even a high-quality one — can be easily defeated. Our London locksmiths are experts in both mortice lock and deadbolt installation, ensuring your security is never compromised.
Need advice on the best lock for your door? Contact Keys4U today for a free security assessment.