Letterblox is a simple and highly effective security letterbox device comprising
solid steel plates secured in place either side of the letterbox aperture by internally accessible knobs. 


Don't Invalidate Your Insurance

The letterbox is the only part of a property that is publicly accessible 24 hours a day and exposes the premises and its occupants to all four main risks as defined by the Insurance industry: fire, water damage, malicious damage and weather-related damage.

Properties that are empty require specialist property insurance and this insurance, in fact, most insurance policies will specify that the letterbox must be adequately sealed.

If you don't seal the letterbox you may find that you are unable to claim on your insurance policy and as such it was a waste of time paying for it in the first place. 

Of course not getting insurance isn't an option especially if you have a mortgage as its compulsory. So don't take the risk of not being able to claim if you have a fire. In fact did you know some insurance policies won't pay out if any aspect of the terms and conditions are breached so by not sealing your letterbox effectively you may not be able to claim for a burst pipe for example.

Crazy but true!

But it's not burst pipe claims you need to worry about; it's complete loss due to fire or worse a liability claim and these can run in to millions of pounds.

97% of all malicious fires are started via the letterbox

When your property is empty one of the most vulnerable parts of the building is the letterbox. In fact the Police and Fire Service report that 97% of all malicious fires are started via the letterbox.

Letterblox is the first product of its kind to protect your property and prevent crime by offering you all of the following benefits:-

  • Solid steel patented design
  • 5 year warranty on parts
  • Universal; fits the majority of door types and letterplate openings
  • Reusable; use again and again for all your empty properties
  • No damage caused to the existing door or letterplate
  • No fixings required
  • No tools required to fit Letterblox *
  • Tested to British and European Standard No.BS EN 13724
  • Received the highly coveted Secured by Design award 
  • Letterblox has been granted a UK Patent No.GB2508818
  • Designed and manufactured in the United Kingdom
  • Fully tax deductible

Protect your property for just £3 a year

Protection of property and assets starts with containing and protecting the most vulnerable part of the property. In most cases this vulnerability is the letterbox. The letterbox offers a clear entry point for perpetrators to access the inside of your building without anything stopping them, until now.

Letterblox gives property owners and managers the ability to stop burglars and criminals in their tracks, limiting their access to the interior at low cost and uniquely with no damage to the existing door or letterbox.

Letterblox ensures your home and assets remain safe from opportunistic criminals, without causing any loss in value to your property through the use of invasive security methods. 

Letterblox truly offers an invaluable source of protection for your home or property.

ATTENTION! HMO landlords and owners/managers of blocks of flats

A fire started in the exit door area (for example as happens in the case of letter box arson) would effectively cut off
the main escape route from the premises.

For these reasons in premises covered by the RRO (Regulatory (Fire) Reform Order) and Building Regulations mandatory legislations state doors used as the final point of exit should be fire resisting (protected); arson proof or fire doors depending on which areas are at risk of fire.

If a risk of fire is applicable to the areas located on both sides of the door, such as the entrance/exit doors of flats and entrance doors that face common areas in HMOs or blocks of flats means making sure the entry/exit door a fire door. In order to be a fire door by its nature there should be no letterbox. This may be costly or impractical so therefore the letterbox should be sealed. Letterblox offers a simple, non-destructive and cost effective way of doing so.

Letterblox can also be used for other purposes not just protecting empty properties from arson attack but also preventing junk mail, stopping 'key phishing' or simply if you prefer to use an exterior post box.

Designed by Landlords for Landlords

Letterblox was designed by landlords Stuart and Lisa Williams following a fire at one of their properties when they nearly lost a £37,000 insurance claim. You can read more about their story on the blog.

You will also read why Letterblox is absolutely crucial to any property owner and should be as important as your insurance policy.

We are honoured to have received the highly coveted Secured By Design award. Secured By Design is the official UK Police flagship initiative supporting the principles of 'designing out crime'.

Our first product is the Letterblox 'Pro' Kit.

We don't know about you but we when we attend a property that needs to be securely sealed we don't have a clue what size the existing letterplate and door sizes are!

As such we realised that when you attend a property you want to be able to fit this device straight away not have to measure up then go back and buy the relevant size.

Added to which the whole point to Letterblox is that you can reuse it as I doubt all your doors and letterboxes are the same size so so we created Letterblox as a kit designed to fit most doors and letterplates.

The 'Pro' kit can be used by anyone but we expect the main users to include:-

  • Landlords
  • Letting Agents
  • Estate Agents
  • Asset Managers
  • Liquidation Companies
  • LPA Receivers
  • Locksmiths
  • Tradesmen


    Letterblox is completely unique in requiring no fixings, being reusable and universal in size.

    Install Letterblox in 3 easy steps:-

    Step 1

    Use the sizing gauge supplied to measure the thickness of the door and use the corresponding knobs and collars as indicated.                                  

    Step 2

    Place the exterior plate into the letterbox aperture. The foam gasket supplied in the box will help keep Letterblox in place while you then fit the interior plate.

    Step 3

    Place the interior plate against the aperture on the inside of the door using the correct knobs and collars to secure the plates against both sides of the door.

     You can also watch the installation video:-

    Frequently Asked Questions

    What is Letterblox?

    Letterblox is a security letter plate device. Essentially no more than two steel plates secured either side of the letterplate aperture with knobs. The knobs only appear on the inside of the property with the outer plate being flat. The solid steel plate and flat against the door design mean its virtually impenetrable to attack. It’s highly likely that someone would break a window or the door itself before getting through Letterblox.            

    Aren’t there similar products on the market already?

    There are indeed a variety of letterbox security devices available on the market. These range from very cheap clips available in DIY stores to very expensive fire boxes and bags. However every single one of them requires fixing to the door or existing letterbox thus they are one off use and damage the door or letterbox. Added to which they are not universal meaning you need to measure the door or ensure that particular device will fit your door or letterbox before attending the property. 

    Why do I need it?

    Emotionally having a fire at your property is very distressing. 

    Financially it can be devastating and it may not just be your property that’s affected. The fire we had at our property was thankfully small and quickly doused but it still caused £37,000 worth of damage mostly due to smoke and water from putting it out.

    The statistics aren’t good; 97% of malicious house fires are caused through the letterbox and that’s why the insurance companies include the clauses they do – it’s due to the claims they’ve experienced.

    What happens to the post I do want?

    If you wish to use Letterblox on an occupied property then it’s likely because you don’t want junk mail, to stop the dog getting to your post first or to avoid key 'phishing' or attack such as fireworks. If this is the case then simply fit an external post box to your property. This massively reduces the amount of junk mail you receive too, especially free newspapers.

    If however you are fitting Letterblox to an empty property then in our experience there isn’t any post you should be receiving at the property. Here’s why:-

    You should ensure that any post that is meant for you is redirected to your home address or an agents as soon as it becomes empty. Having any post addressed to you going elsewhere is a risk to identity fraud or worse. It is not unheard of for tenants or strangers to claim to be the property owner and properties have even been sold without the actual owner knowing!



    You don’t want tenants post. As soon as the tenant or previous occupier moves out of the property you should notify the utility companies and council and arrange for post to come to you.

    It is illegal to throw away or open another person’s post and when your tenants move on you should not be opening their post or even taking receipt of it in order to dispose of it. 

    Under the Postal Services Act 2000

    “A person commits an offence if he, without reasonable excuse, intentionally delays or opens a postal packet in the course of its transmission by post, or intentionally opens a mail bag.”

    “A person commits an offence if intending to act to a person’s detriment and without reasonable excuse, he opens a postal packet which he knows or reasonably suspects has been incorrectly delivered to him.”

    This, in essence, means that if you deliberately intercept, throw away or open somebody else’s post you are likely to be breaking the law.

    The only people allowed to open it are witnessed Royal Mail staff so if the post cannot be delivered it will be returned to the post sorting office and then returned to the sender thereby notifying them that the tenant or previous occupier has moved on.

    This is crucial to avoid bills continuing to be logged at the property in someone else’s name and risking CCJs, bailiff visits and court orders as a result.

    Will Letterblox not alert someone to the fact the property is empty?

    Letterblox can be used on occupied properties as well as unoccupied so just having Letterblox in situ doesn't mean the property is empty. During our research we saw many varied ways of sealing letterboxes; none of which imply the property is either occupied or unoccupied. Letterblox simply creates a far more secure, neater and non-destructive way of doing the job.

    The aim of Letterblox is to deter attack via the letterbox and ensure you are able to claim on your insurance policy should an insurable claim take place. Indeed our letterbox was in fact taped up and it didn't stop the attack however it did mean we could claim on the insurance and weren't out of pocket by £37,000.

    The flat plate design in white suits the most common white UPVC doors and won’t be immediately obvious to anyone passing.

    We are currently designing mock fronts in other colours and designs for aesthetic purposes and to create the impression of a normal letterbox should this still be of concern to you.



       Prevent and Protect

      * You may need a screwdriver to remove and replace the original letterbox but no tools are required to fit Letterblox itself.