Geograph - photograph every grid square

This is a rare example of a concrete Hyperbolic-paraboloid structure. Built in 1960-61 to designs by architect Hugh Segar (Sam) Scorer and structural engineer Dr Hajnal-Kónyi, it was originally a canopy to a petrol filling station, and provided a striking appearance in comparison with the bland examples of the general run of filling stations. In the late 1980s it ceased to be used as a filling station and a restaurant, latterly a Little Chef, was built within the structure. Following the redevelopment of the A1/A57 interchange at Markham, with newer services facilities, the site became redundant.

The importance of the structure is recognised by a Grade II listing. This makes the following points:
"* Technical innovation: it is a particularly direct example of a hyperbolic paraboloid roof, an unusual and dramatic roof solution which was then being experimented with by a number of architects and engineers all over the world.
* Architectural interest: it is a dramatic piece of concrete design which displays the hyperbolic paraboloid form in a daring manner.
* Architectural authorship: the team of Scorer and Hajnal-Kónyi was advanced in the design of hyperbolic paraboloids. Scorer is chiefly remembered today for his three buildings that are substantially roofed in hyperbolic paraboloid shells, two of which are listed, one at Grade II*.
* Architectural distinction: during a period when standardisation of petrol stations was introduced as an aid to product recognition, the example at Markham Moor is unique by virtue of its technical innovation and individual design.
* Rarity: it is one of few extant hyperbolic paraboloid shell structures from the 1950s and 1960s.
* Intactness: The canopy and four structural supports remain intact and uncompromised by the inserted building beneath."

The roof shell is simply supported on four columns at the lowest points of the sides - the later restaurant building's walls do not provide any structural support to the canopy. The low points are only 5 feet above ground, the apexes are 37 ft 4 ins high, and the dip in the centre provided a headroom of around 18 ft.

The location relative to the current road junction layout means that it is unlikely to find a new occupant as it stands, the only practical solution being to find a new access from the north side. What its future will be can only be considered uncertain.

The A1 is the longest numbered road in the UK at 410 miles long. It connects London with Edinburgh, via the east of England.
For much of its path it follows the Great North Road the old coaching route between London and Edinburgh. Several sections of the route are classified as motorway A1(M). The modern A1 bypasses the towns the Great North Road passed through and is dual carriageway for most of its route through England.

Listed buildings and structures are officially designated as being of special architectural, historical or cultural significance. There are over half a million listed structures in the United Kingdom, covered by around 375,000 listings.
Listed status is more commonly associated with buildings or groups of buildings, however it can cover many other structures, including bridges, headstones, steps, ponds, monuments, walls, phone boxes, wrecks, parks, and heritage sites, and in more recent times a road crossing (Abbey Road) and graffiti art (Banksy 'Spy-booth') have been included.

In England and Wales there are three main listing designations;
Grade I (2.5%) - exceptional interest, sometimes considered to be internationally important.
Grade II* (5.5%) - particularly important buildings of more than special interest.
Grade II (92%) - nationally important and of special interest.

There are also locally listed structures (at the discretion of local authorities) using A, B and C designations.

In Scotland three classifications are also used but the criteria are different. There are around 47,500 Listed buildings.
Category A (8%)- generally equivalent to Grade I and II* in England and Wales
Category B (51%)- this appears generally to cover the ground of Grade II, recognising national importance.
Category C (41%)- buildings of local importance, probably with some overlap with English Grade II.

In Northern Ireland the criteria are similar to Scotland, but the classifications are:
Grade A (2.3%)
Grade B+ (4.7%)
Grade B (93%)

Read more at Wikipedia Link