On a clear day, you can see the benefits

A 'big sky' has become the urban version of green space for those who are prepared to pay the price

There is nothing like a stunning view for making a first impression. It doesn't matter whether it is over water, hills or rooftops, the wow factor adds a dimension that even the best design cannot compete with.

There is nothing like a stunning view for making a first impression. It doesn't matter whether it is over water, hills or rooftops, the wow factor adds a dimension that even the best design cannot compete with.

It is not so easy to put a value on a view in the countryside, where houses cannot be compared like with like, but in cities an exceptional outlook can command a premium of as much as 30 per cent. A "big sky" has become the urban version of green space, and nowhere is the impact greater than from a penthouse apartment.

In blocks where they did not exist, new floors have often been added to meet the demand for innovative design, generous room size and the sensation of living at the very top of a building. At Point West, the revamped development on the Cromwell Road, west London, that was once the British Airways terminal, 12 penthouses have been reserved over the past two weeks at prices between £950,000 and £2.5m. The largest apartment is more than 3,300sq ft and the combination of size, height and location within Kensington and Chelsea explains the interest.

But views of the London Eye and Natural History Museum are not enough. Jonathan Holman, sales and marketing director of developers Regalian, says show apartments are important if buyers are to get an idea of how best to use the unconventional space over three floors. "We have couples who want just one bedroom with an office as well as families, but they all like to see what can be done." They can also make use of the concierge service for the top floors that could save penthouse owners from having to walk the dog or get their own theatre tickets.

Isolation without the status was something to be endured by anyone living in a tower block before the developers moved in. Council tenants may have had a view but they also had dodgy lifts and filthy stairwells. Families with young children suffered the most, and as flats fell empty they were easier to fill with the young and childless. A man who spent his student years on the 20th floor of a council block recalls the dilapidation vividly, but still misses the view: "The window was a vast sheet of glass broken up by the door to the balcony. Anyone who visited us for the first time just stood there in amazement. We looked out over the City and St Paul's. It was surprisingly noisy because even though we couldn't see the street, we could hear it."

Just such a tower block in Bethnal Green has recently gone through an £8m refurbishment with its private owners. Instead of crumbling masonry and graffiti covered walls, it now has a glass and aluminium entrance hall, new cladding and a water feature. Keeling House, saved from demolition after it was listed, now comprises 64 smart flats, eight of them penthouses priced from £375,000. These are on three floors with wrap-around balconies and tremendous views.

Even a good view is graded. John Callander of De Groot Collis, the selling agent for the Parliament View scheme, south of Lambeth Bridge, says the difference between a view of the river and a view of the river across to the Houses of Parliament equates to 20 per cent. "A building without either view would be worth only 60 per cent of the best prices we have achieved."

Partly on the strength of the view over the Thames Barrier, Barratt is selling off-plan apartments in the tallest building it has ever constructed. Barrier Point at Silvertown will have two penthouses at the top of the 165ft tower. They will not be launched until the autumn and are not likely to cost less than £750,000.

In the country, a lovely view is almost always on a buyer's list. Rupert Bradstock, from buying agents Property Vision, says 95 per cent of people want a view over unspoilt and protected countryside. "The greatest view is over your own land, but if you can't have that then an area of outstanding natural beauty comes close because you know it can't be developed. The only disadvantage to a view is that you also get the wind, but it is a small price to pay. We have had people buying purely on the strength of a stunning view, even when the house was not quite what they were looking for."

In south Devon, Tony Harris, who is selling his house, knows the power of spectacular scenery. From Warren Cottage, in its sheltered spot on the cliffside surrounded by National Trust land, he can look past the Eddystone lighthouse along the Cornish coast. "We see the sun rise and set and it is never the same. We have learnt to predict the weather by how clearly we can see the lighthouse, which is visible while lying in bed. The sound of the sea is extraordinary too. The drama of the waves pounding in a storm is electric but so is a gentle sea, especially at night."

He sums up the attachment he feels to the natural environment as being in the role of a custodian. "We do feel responsible for preserving it and for the wildlife. My wife and daughter were befriended by a seal who would appear every time they went swimming. The bird life is magnificent, a golden eagle appeared out of the blue recently and stayed for a few weeks. After 15 years, we will miss living here."

At the other extreme of the country, a laird's house perched on the shores of Loch Eishort on Skye has views over the water to the Cuillins. By the standards even of Skye its position is remarkable. In all likelihood it will be used as a holiday home and agents Finlayson Hughes has already had inquiries from the United States and Dubai.

When it comes to views, Gladys Stone, a widow in her late seventies, knows all about losing them. Last year she was involved in a court battle after refusing to move out of her Mayfair home - which was going to be redeveloped - saying she would miss watching the world from her window. The judge accepted she was passionately attached to her home and noted her apartment had the best views over London he had ever seen. But he concluded that her housing needs did not require such a view and she would have to go.

Further Informnation

Point West sales office, 020-7373 3100; Barrier Point, 020-7511 4139; Warren Cottage, £450,000, through Marchand Petit on 01548 831163; Keeling House, through Felicity J Lord on 020-7481 8811; Ord House, Isle of Skye, offers over £200,000, through Finlayson Hughes on 01463 224343