Architecture: No more nasty doorways in Alnwick, thanks: Local authorities will soon be able to veto inappropriate decoration of houses in conservation areas. This is welcome news for John Smith

In conservation areas up and down the country there are home owners preparing to spit blood. They are girding themselves to fight, not on the beaches but on the pebble-dash. For soon the right to disfigure fine houses, however humble, with all that is fake, plastic and gimcrack will be curtailed. And about time.

After months of consultation with bodies such as English Heritage and the English Historic Towns Forum, the Department of the Environment has said that local authorities can set their own rules about what is and is not appropriate in the external decoration of homes in the 8,000 conservation areas of England and Wales.

The legislation cannot come soon enough for towns like Alnwick in Northumberland. Here a fine architectural cohesiveness has been blighted by inappropriate updating.

Alnwick is a county town with a tough, gritty elegance. It has a castle, a medieval gate and a fine collection of 18th- and 19th-century two- and three-storey stone buildings. The centre has a handful of streets - broad and narrow, straight and curved - and a small market-place. It seems marvellously unspoilt until you notice the blight of late 20th-century doorways, windows, shop fronts, signs and lettering.

Doorways are a particular irritant. One common architectural feature in Alnwick is the use of single, well-proportioned entrances, each serving a pair of houses. Beneath an attractive double fanlight, there are two front doors, one for each of the adjoining dwellings. The design quality is far superior to that which would have been achieved by the ordinary solution of two openings side by side.

Frequently, however, the original harmony of these shared entrances is ruined because the occupants of the two dwellings have asserted their individuality by painting their respective halves contrasting colours. Worse has been the replacement of pairs of splendid six-panelled doors for 'do-it-yourself' versions.

Modern buildings also suffer. A well-designed terrace of council houses in stone, with slate roofs and white-painted timber porches, has recently been improved for the worse. As each house has been sold the proud owner has rushed to the DIY superstore and fitted an inappropriate dark-stained hardwood door with poorly proportioned glass panels.

And then there are the shops. These are regulated by strict planning laws, yet many original shop fronts are disfigured - quite legally - with plastic fascias. The law regarding advertisements and business premises allows fine architectural detail to be covered by shop signs. The Department of the Environment's new legislation will do nothing to close these loopholes.

In Alnwick the original business premises, with their classical shop fronts, are as valuable as the town's domestic architecture. Since the designs are based on the Greek orders of architecture, you find display windows and doorways framed at their sides by pilasters and at first-floor level by entablatures.

An entablature has three elements - an architrave, a frieze and a cornice. In other words, it is an assembly of mouldings - curved, flat, projecting and recessed - which use light and shade to create a lively architecture that has never been bettered. Moreover, the feature forms an ornamental unit in scale with the total composition of the building.

The flat plane of the frieze provides an ideal place for the name of the shopkeeper with the added benefit that it also controls the size of the lettering. The pilasters are often fluted and capped with carved consoles - one shop has the head of a fox carved above each pilaster.

Happily, Alnwick has managed to keep some of these treasures; but many more have been covered by sheets of hardboard or plastic. In some cases an even cruder, larger fascia has been created by lowering the shop window.

Signs and advertisements for shops and businesses fall into two classes. There are those that are necessary, such as the name of the shop or business, and those providing gratuitous descriptions of individual items for sale. The second class of signs could be dispensed with for the sake of visual improvements.

One of the best buildings in the market-place is the old town hall (1771) which has an interesting external staircase and stately windows with moulded stone architraves. But two of the ground-floor windows have been removed and a badly proportioned shop front inserted. Several of the stone frontages in the market have been pebble-dashed or painted.

Shop owners, councillors and town-hall officials need to understand two facts. First, in shopping streets the public is unaware of anything above shop-window level. Point out some of the lovely architecture that exists above first-floor level and most people are amazed. Second, the best advertisement for any shop or business is not a plastic sign but the quality of the display in the window.

Shopkeepers might protest that if you take away their garish signs they will lose business, but there is no disadvantage if all shops in an area are obliged to follow the same rules. And any code of design must take account of the needs of different sorts of environment. It is pointless to apply the same rules to all thoroughfares, broad and narrow, formal and informal.

What each conservation area requires is an intelligent grammar of public design that respects the achievements of the past and the needs of the present. Buildings, no less than people, need to be good neighbours if they are to do justice to each other's character.

(Photographs omitted)