A mountain of illegally dumped rubbish blocking an entrance to Frays Farm Meadows was found by London Wildlife Trust staff on Thursday morning.

The works entrance to the nature reserve, accessible from a slip road on the A40, was completely blocked by several truckloads of waste.

Despite its location next to the busy A40, Frays Farm Meadows is an important nature reserve, home to endangered water voles, barn owls, slow worms and a colony of glow-worms.

The reserve is so important for wildlife that most of it is designated as a Site of Special Scientific Interest, one of only 37 such sites in the entire Greater London region.

The Trust keeps grazing Sussex cattle on the Meadows at this time of year to help maintain plant diversity and keep scrub in check without using heavy machinery. Eleven cattle are currently on site, happily munching on the coarse grasses that grow in the wet and boggy meadows, but it is essential that the works entrance is kept free so that they can be reached by vehicle if need-be.

Staff from London Wildlife Trust are working to clear a route through the rubbish and Highways England has said they will help remove the discarded waste.

A spokesman for the Trust said it is fortunate that the dumped waste is only blocking a work access route and will not directly affect the wildlife or visitors’ enjoyment of the Meadows.

Simon Hawkins, the Trust’s conservation officer for west London, said: “This is very serious episode of flying tipping - it's not a couple of bags of garden rubbish out of the back of someone's car, but truckloads of sub soil, rubble, fencing panels, car batteries, large empty blue drums of cleaning fluid and what looks like the contents of a house.

“It's taken up staff time clearing it back so the farmer can get access to the cattle, and could have cost London Wildlife Trust a lot of money to remove. Fortunately Highways England has said they will remove the rubbish because it's blocking their access to the A40 viaduct.”

London Wildlife Trust provides more than 40 free-to-visit nature reserves across London. For more information see www.wildlondon.org.uk.