Mill Hill Substation Pastures is a fifteen hectare Local Nature Reserve

Local Nature Reserve

Local nature reserve or LNR is a designation for nature reserves in the United Kingdom. The designation has its origin in the recommendations of the Wild Life Conservation Special Committee which established the framework for nature conservation in the United Kingdom and suggested a national suite...

, a Site of Metropolitan Importance, in Mill Hill

Mill Hill

Mill Hill is a place in the London Borough of Barnet. It is a suburb situated 9 miles north west of Charing Cross. Mill Hill was in the historic county of Middlesex until it was absorbed by London...

 in the London Borough of Barnet

London Borough of Barnet

The London Borough of Barnet is a London borough in North London and forms part of Outer London. It has a population of 331,500 and covers . It borders Hertfordshire to the north and five other London boroughs: Harrow and Brent to the west, Camden and Haringey to the south-east and Enfield to the...

, England.

The reserve consists of pastures grazed by horses around Mill Hill Electricity Substation. These contain patches of unimproved London Clay

London Clay

The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...

 grassland. Locally uncommon plants include devil's bit scabious

Succisa pratensis

Succisa pratensis Moench, also known as Devil's-bit Scabious, is a flowering plant of the genus Succisa in the family Dipsacaceae. It differs from other similar species in that it has 4 lobed flowers, whereas Small Scabious and Field scabious have 5 lobes and hence it has been placed in a separate...

, sneezewort

Sneezewort

Achillea ptarmica is a species in the genus Achillea. It has loose clusters of white, button-like flowers that bloom from June to August...

, pepper-saxifrage and red bartsia. The dividing hedges appear to be very old, and Burtonhole Brook, a tributary of Folly Brook

Folly Brook

Folly Brook is a 2¼ mile long brook in the London Borough of Barnet. It is a tributary of Dollis Brook, which is a tributary of the River Brent, which is a tributary of the River Thames....

, flows through the site, adding to its diversity of habitat. Breeding birds include spotted flycatcher

Spotted Flycatcher

The Spotted Flycatcher, Muscicapa striata, is a small passerine bird in the Old World flycatcher family. It breeds in most of Europe and western Asia, and is migratory, wintering in Africa and south western Asia. It is declining in parts of its range....

.

The reserve is on private land, but can be viewed from Burtonhole Lane and Partingdale Lane.