Along her journey, Helen encounters the remarkable people, plants and animals living above, beside and beneath the motorway, and delves into the controversial history of the UK’s longest and least-loved bypass.
The M25 has been part of Britain’s landscape for nearly 35 years, so how has the world the motorway carves through adapted to the road? Starting just south of the Thames at Kent’s junction 1, Helen explores the woodlands that line the first 40 miles of the M25. In a first sign of how animals lives are shaped by the man-made world, great tits are changing the pitch of their calls in order to be heard above the roar of the road.
Autumn rains trigger fungi to emerge into the roadside woodland. One species, Neurospora, offers a potential solution to our congested highways. Neurospora’s mobile DNA flows smoothly around an incredibly complex network of fungal freeways. Scientists are trying to figure out the fungi’s secret, in the hope of one day inspiring more robust transport networks.
The Western arc of the motorway crosses many rivers and canals. Helen dives into the serene spaces created in gaps between the motorway and the waterways. Local author J.G. Ballard was also obsessed with the hidden spaces around our urban infrastructure, using them as settings for his dystopian novels.
Where the M25 crosses the river Thames, Helen searches for plant life on the damp concrete beneath the motorway. Mosses are often overlooked, but Natural History Museum botanist Dr Silvia Pressel reveals that the drought-resistant properties of these primitive plants are key to how plants made their move from water to land. This huge leap 500 million years ago paved the way for all today’s land plants, and us mammals that rely on them.
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