The Ultion Nuki smart lock

The new type of lock can be opened in several ways, including by scanning your fingerprint

For homeowners given to forgetting their keys, leaving a spare set with a neighbour or under a plant pot have for a long time been the only options to avoid being locked out.

But a new type of lock is offering an alternative to the forgetful - as you can open it by scanning your fingerprint.

The British-made Ultion Nuki appears, at first glance, to be just a normal door lock with a key. In fact, for those put off by technology, it can be used like that.

But the "smart lock", which fits any normal UK door, has several additional ways to unlock the door.

The idea is to appeal to those who regularly misplace their keys, or simply don't want to carry keys around with them. Some of the features are also handy for those who don't want to leave keys under a plant pot for, say, the dog walker or cleaner.

As well as entry via a fingerprint scanner and a normal door key, the lock can be opened and closed using a smartphone or watch, a code tapped into a keypad, or even voice if users set up a "voice pin".

And Ultion bosses are also now working on facial recognition - so people can unlock their door with their face. It would use a small camera and work like the Face ID feature on iPhones.

Nick Dutton, boss of Ultion parent company Brisant-Secure, said: "It might seem a bit sci-fi but the whole point of smart home security is to make life easier and more convenient for people - while not compromising on the core function of keeping the bad guys out.

"You can't consider something to be truly smart if you restrict or take away functionality, which is why fingerprint entry is just the latest option - alongside voice, app, smartwatch, and a normal door key if users prefer.

"Now that fingerprint access is a reality I could see how this could evolve into facial recognition that many of us already use on our smartphones. But the technology would need to be 100 per cent secure before we consider implementing it."

Unlocking convenience for your front door is not cheap. The Ultion Nuki smart lock - without the new fingerprint feature - is £239. It fits most UK doors.

Fingerprint entry is via a sensor on the add-on keypad, which costs £145.

Bundles bring the combined price to £390. Prices are expected to come down once the technology is more established.

The keypad has an extra security feature that limits usage to specific dates and times - meaning it can be blocked from opening the door at night time or when owners are on holiday.

Yale has been the market leader in locks and keys in the UK for years, but its attempts to move into so-called smart locks have not taken off.