A new tracking tool has been launched to identify Japanese knotweed sightings across the UK.

The heatmap, Exposed, provides an interactive online locator of sightings.

Exposed has revealed that there are 46 infestations of the UK's most invasive plant within 4km of Reading town centre and 26 infestations within 4km of Slough - suggesting that Berkshire homeowners should be vigilant, particularly when buying or selling a property.

Designed to inform homeowners and potential homebuyers of the local presence of knotweed and the potential risk to their property, Exposed has already been populated with thousands of infestations by leading Japanese knotweed firm Environet UK, which has operated across the UK for more than 20 years.

It allows members of the public to enter a postcode to discover the number of reported knotweed sightings nearby.

Knotweed hotspots are clearly visible in yellow or red.

The general public is encouraged to help populate the heatmap, which is the only live tool of its kind, by reporting infestations using the ‘add sighting’ feature and attaching a photograph of the plant so it can be verified by experts.

Introduced to the UK in the 1840s as an ornamental plant, Japanese knotweed now grows rampantly along railways, waterways and in parks and gardens and is notoriously difficult to treat.

Its presence can prevent a mortgage lender approving a loan and therefore impact a property’s value by up to 10 per cent.

Described by the Environment Agency as "indisputably the UK’s most aggressive, destructive and invasive plant," Japanese knotweed’s rapid spread across the UK has prompted a Parliamentary Inquiry into its impact on the built environment, which is expected to release its findings this spring.

Where a high number of knotweed sightings appear nearby, potential homebuyers may wish to instruct a Japanese knotweed survey to check the likelihood of the property they intend to buy being affected or at risk of encroachment from infestations in the vicinity.

However, if no sightings are shown locally, this does not guarantee that knotweed is not present, as it may not have yet been reported.

Nic Seal, founder and MD of Environet, who created Exposed, said: "This heatmap will help us build a nationwide picture of the Japanese knotweed problem and give the general public the information they need to assess the risk in their local area.

"Berkshire is a Japanese knotweed hotspot, particularly around larger towns such as Reading, Bracknell and Slough.

"Exposed will be a useful tool for those buying and selling property in the county and local residents who want to be aware of infestations near their homes which could spread, putting their property at risk."

Homeowners who are concerned about knotweed infestations near their home could consider purchasing a specialist Japanese knotweed indemnity policy, which covers them for the cost of treatment, repairs, legal costs arising from third party claims and any diminution of the property’s value, should knotweed arise.

To view Japanese knotweed infestations in your area or to report a sighting, please visit: https://environetuk.com/exposed-japanese-knotweed-heat-map-information.