Brookmill Nature Reserve consists of part of a disused railway embankment between Brookmill Road and the busy lines from Lewisham to St Johns.
The railway from Nunhead to Blackheath Hill was opened in 1871, and in 1888 extended on to Greenwich Park. Never a great success, the railway ceased operating at the end of 1916 as a wartime economy measure, and after the war it was left to quietly decay.
The section west was re-routed to connect directly to Lewisham in 1929, while the section through to Greenwich Park was formally abandoned in that year and the tracks taken up.
It was left to its own devices until 1979 when Lewisham Council purchased the freehold of the land from British Rail. Local people took an interest and, with the help of staff from the nearby Ashmead Primary School, formed a small overseeing committee for the Council’s first nature reserve. In 1981, the newly-formed Lewisham Group of the London Wildlife Trust prepared a management plan, and established a series of regular working parties.
The intention was to create an educational site with as many habitats as possible represented in a small area, and this has been largely successful, due in no small part to the efforts of David Larkin, a local London Wildlife Trust member who has put enormous amounts of time into the management and monitoring of the site.
The steep sides of the embankment are wooded. Sycamore was
the dominant tree before management began, but many of these were removed and replaced with native species such as hornbeam and hazel. A large plum tree was retained, and provides abundant fruit in late summer for visitors to the reserve - both avian and human.
The reserve is kept locked, but there are regular conservation work days.
The site is well used by local schools for environmental education.
The natural ground flora of bramble, ivy and cow parsley has been supplemented by planting of species such as yellow archangel and wood anemone. Some of the introduced plants, including wood anemone, greater stitchwort and gorse, were rescued from the William Curtis Ecological Park, beside Tower Bridge, when the park was cleared for development in 1985.
An unusual botanical feature of the reserve is a dense stand of stag's-horn sumach. This North American tree is popular in horticulture for its furry twigs and clusters of tiny, red flowers, but rarely seeds itself away from gardens or reproduces in the wild to the extent seen here.
A path winds up through the woodland, climbing the steep slope by means of steps, to reach the flat top of the embankment. This area was seeded some years ago with a chalk grassland mix, resulting in a colourful summer display of salad burnet, common bird’s-foot-trefoil, oxeye daisy, hedge bedstraw and wild marjoram.
Additional plants were grown from seed by the Council’s parks department (as it was then) and planted out in autumn 1986. Of these, meadow and bulbous buttercups have flourished, and meadow crane's-bill and nettle-leaved bellflower can still be found. To the east of the chalk grassland, bramble scrub provides cover and food for foxes and for birds such as long-tailed tit, blackcap and lesser whitethroat, which are unusual in such an urban location.
Three small ponds have been created, each using different construction techniques to produce different characters. A raised pond just inside the main gate, created by people serving community service orders with the local probation service, provides pond dipping opportunities for people with disabilities.
A much more extensive pond below the embankment on the southern edge of the reserve has a marsh of reed sweet-grass and greater spearwort at one end, and is crossed by the main path on a wooden bridge. The third pond is a sunken water tank in the grassland on top of the bank. The latter two ponds, at least, support breeding frogs and smooth newts. Common darter dragonflies are frequent visitors and may breed.