According to a freedom of information request by The Times, the state-owned company has received 11,000 complaints about the weed since 2011. The figure includes more than 6,000 complaints that the plant was spreading to private property from Network Rail land.
The number of complaints lodged each year against Network Rail, which owns and maintains the UK rail network and adjoining land, has increased by 70 per cent between 2012 and last year, according to the newspaper.
Japanese knotweed is known to be a danger to property and has an intricate root system that can wedge itself between cracked brickwork and can block drains and damage building foundations.
Nic Seal, founder and managing director of Environet UK, said: “Complaints to Network Rail from homeowners regarding Japanese Knotweed have increased by 70 per cent between 2012 and 2018, which goes to show how voraciously the plant is spreading along Britain’s railway lines and suggests a growing awareness among homeowners of the risks to their property.”
He added that simply treating infestations with herbicide where homes are under threat is not enough, because homeowners are required by mortgage lenders to produce an insurance backed guarantee for the work when they sell. Network Rail does not provide such guarantees, which are typically offered by private firms.
“Without the guarantee, homeowners find themselves trapped in their homes, unable to sell, rendering their homes effectively worthless. This is unfair and unjust.
“Network Rail must face up to its responsibilities and take action now to remedy the situation by swallowing the cost of offering guarantees to homeowners for treatment work,” Seal concluded.
In May, the government’s Science and Technology Select Committee called for more academic research to establish the impact of the Japanese Knotweed on the built environment.