In one of the most memorable scenes in the Beatles film Help!, the Fab Four draw up in a car outside a row of terraced houses. Each unlocks his own front door, but this is a ruse to show that they are still down-to-earth boys from Liverpool. For, as the next scene reveals, the houses have been made into a single luxurious bachelor pad. The craze for knocking through was born.

In subsequent decades, the popularity of turning two — or more — houses into an extra-large home may have waned in favour of the sub-division trend. Developers were keen to maximise their profits by creating eight flats from one family house. But now bigger is, once more, officially better, which means that partition walls are out and sledgehammers are in.

Jamie Oliver, the chef who is worth an estimated £40 million, is so enamoured with his home in Primrose Hill, North London, that he has bought the house next door and is knocking the two together to create a £7.5 million superhome. House number two will be painted the same canary yellow as the original, the front balconies will be realigned so that they are on the same level and an adjoining wall will be knocked down to create one huge reception room. The only telltale sign that the house was once two will be the two front doors.

Agents say that knocking through has gained popularity as homeowners who want more space become increasingly wary of moving. Some do not want to uproot their families; others fear annoying new neighbours. Louis Winterbourne, of Savills, has seen “a handful” of such cases in the past year. “There is an ‘improve, don’t move’ mentality that has become much more common over the past 18 months,” he says.

Taking on such a project may seem daunting, but it can cost as little as £30,000 to turn two properties into one if the house next door is a mirror image of your own. Clever planning can get the job done in a couple of months, leaving the most intrusive bit — the knocking down of the central wall — until last. Knocking through will be much more expensive (at least £100,000) and less worthwhile, however, if the two houses are completely different, Winterbourne says, because staircases have to be moved and floors realigned. “About half of such projects look disjointed. Whether they feel natural or not is often down to the original structure rather than any fault with the restructuring design.”

Old Palace Place, a Grade II* listed mansion overlooking Richmond Green, southwest London, and on the market for £7 million with Knight Frank, has an advantage for a buyer hoping to do a conversion of this kind. The house, which has six bedrooms and a 124ft garden, was once joined to the house next door, which, by coincidence, is also on the market, for £2.5 million via Savills. The two were one residence for 60 years and were divided back into two separate homes in 1983, when the second front door was reinstated. The smaller house has four bedrooms, plus a self-contained apartment and an even larger garden than its neighbour. There is no existing planning permission for such a project because no one has owned both houses since the split, but agents think that, given its history, planners should not object.

Gary Bullard, the current owner of the larger house, says that the two would look perfect as one, and that the smaller house would make excellent staff and guest lodgings. However, Mr Bullard, who runs a PR agency for women executives, has no plans to do so himself. “I think it would be a bit too big for just me, my wife and our three cats,” he says.

But will two homes hold their value if they are turned into one? In some cases, properties may even gain in value, depending on their surroundings, according to Dawn Carritt, of Jackson-Stops & Staff. If they are on a street that is lined with unimpressive semis, this will drag down the value of your new home, possibly even below what the two houses would have fetched separately. However, if the other houses on the street are large and yours is the odd one out, it will definitely benefit from an upgrade.

One of the most important things to take into account early on is planning consent. If the property is in a conservation area, making a substantial change to the garden or the façade may be difficult. And it is likely to be much trickier if one of the properties is listed. This is certainly true in the case of Sloane House, a sixbedroom Georgian property just off the Kings Road in Chelsea, which Sir Anthony Bamford, chairman of JCB, the construction equipment group, bought in 2004. The property is now for sale at £79 million, but it comes with Sloane Lodge, the neighbouring cottage, which Bamford originally wanted to knock together with the main house to create a 24,000 sq ft mansion. He bought both properties together for £45 million. Permission to merge the two has been granted — but only to join them at ground and basement level. Aylesford International, the joint agent with Beauchamp Estates, thinks that the two may well be sold separately.

Andrew Langton, chairman of Aylesford International, adds: “The conversion, including the installation of a swimming pool and an overhaul of the plumbing, would probably cost about £15 million.”

Buyers who want more space but not the hassle or expense of building, could always copy Tony Blair’s example in Connaught Square, Mayfair, and buy a neighbouring mews house. This will provide space for your guests but maintain the privacy and integrity of your original home.

Chetwood has designed a series of transparent purpose-built MP pods close to the House of Commons and attached to Westminster Bridge, which itself would be transformed into a pedestrianised public space.

He has also suggested similar office pods, to allow MPs to interact with the public in their constituencies, allowing voters easy access to their elected representatives.

"We were looking at images of the Houses of Parliament – it's a lovely building, but it's not exactly transparent, it almost encourages people to get up to no good," said Chetwood.

"We thought mixing the accommodation with something public would make it more transparent. And everything's below the parapet so it respects the [protected] views."

Chetwood said he had first started thinking about MPs' accommodation after former

Lib Dem leader Ming Campbell suggested putting politicians in the old County Hall building on the south side of the river.

He said the two sets of pods – in constituencies and in Westminster – would foster more interaction between voters and politicians.

"I'm not even sure how to contact my MP, or where their surgery is,” he said. “This would be a neutral space where you can meet your MP."

Chetwood added that he hoped the honeycomb like design would inspire its occupants, saying: "It's got that industriousness to it – hopefully it would get some work out of the MPs."

10 Breathtaking Viewing Platforms Around the World

1. Dachstein Sky Walk (Austria)

Nicknamed the "balcony of the alps," the Dachstein Sky Walk is formally enthroned at 2,700 m above sea-level, high up on the 250 m vertical rock face of the Hunerkogel. A 360 degree panorama allows the visitor a view of Slovenia in the south to the Czech Republic in the north. The Sky Walk is distinctly higher than the platforms of the Niagara Falls or even the one at the Iguazu waterfalls in Brazil.

2. Aurland Lookout (Norway)

Architects Todd Saunders and Tommie Wilhelmsen were commissioned to design a scenic rest-stop 2'000ft above Aurland fjord in Norway and came up with this beauty wining the first prize in Norwegian tourist routes competition. The outermost end of the horizontal platform - which curves to form the structure's support - is closed off by a sheet of glass, offering an incredible view towards the ground for all those with the guts to make the trip to the end.

3. Grand Canyon Skywalk (Arizona - USA)

This horseshoe-shaped pant-filler hangs approximately 4000ft above the floor and extends 65ft beyond the edge of the Grand Canyon. The Horseshoe shaped skywalk is constructed of glass walls 4 inches thick and visitors must don special scratch-proof socks as they partake in the view. The work is a true engineering feat that can hold up to 70 tons (roughly 14 African Elephants) and withstands winds of 100mph.

4. Suspended platform at Iguazu Falls (Brazil and Argentina)

While the falls themselves are magnificent, their setting in a huge subtropical nature reserve makes visiting even more enjoyable.

To fully appreciate their size and splendor it's worthwhile viewing the falls from the skywalk. The viewing platform is so close you are instantly drenched by spray and deafened by the roar of water plunging over an 80 metre cliff.

5. Auckland's Sky Tower (New Zealand)

Auckland's 328m Sky Tower is the southern hemisphere's tallest structure. It took 2000 tonnes of reinforcing steel, 660 tonnes of structural steel and 15,000 cubic metres of concrete to erect it. It can withstand 200km/h winds, earthquakes up to eight on the Richter scale and on a clear day, visibility is around 82km. The highest indoor point is Sky Deck, which has seamless glass giving unimpeded 360º views.

6. Illawarra Fly Tree Top Walk (Australia)

This walk opened recently after five months of construction. Located at Knights Hill up high on the escarpment near Robertson in the Southern Highlands, the Illawarra Fly Tree Top Walk allows visitors to walk among the rainforest canopy 25 metres above the ground on a steel platform. The 500m elevated walkway features cantilever arms that take visitors to the edge of the escarpment and offer inspiring views of the coastline from Kiama through to Shellharbour.

7. Landscape Promontory (Switzerland)

The landscape promontory is a suspended viewing platform designed by Paolo Bürgi as part of the Cardada project, a revitalization of the Cardada mountain that is expected to finish in 2010. The passageway is made of steel and titanium leads to the lookout platform with a view of Lago Maggiore. The landscape panorama is not the only thing that visitors are meant to appreciate. Symbols in the paving with accompanying texts in the railing provide references to history and literature.

8. Infinity Room at House on the Rock (Wisconsin - USA)

The House on the Rock, originally opened in 1959, is a complex of architecturally unique rooms, streets, gardens and shops designed by Alex Jordan, Jr. It is located in Spring Green, Wisconsin and is a regional tourist attraction. The Infinity Room at the House extends several hundred feet over the valley, without supports underneath, and is lined with over 3000 handmade windows.

9. Il binocolo (Italy)

Within the gardens of Trauttmansdorff castle in Italy you'll find this charming steel platform poking out through the trees, its name (meaning 'the binoculars') coming from the shape of the platform's small roof and the view of the surrounding landscape. Designed by architect Matteo Thun.

10. Top of Tyrol (Austria)

Top of Tyrol by Astearchitecture is a viewing platform located 3,000 m above sea level at the Stubai Glacier in Tyrol, Austria. Weathering steel was used in the construction of this structure to account for the extreme weather conditions so you can stand 9 metres away from the mountain with a perfect view of Stubai glacier.

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