The CPRE report – Green Belt under siege: the NPPF three years on – concluded that more than 219,000 houses are planned for the Green Belt, 60,000 more than CPRE’s last count in August 2013. It warned that the number of houses planned on protected land has almost trebled since 2013 despite David Cameron’s recent protestations that the Green Belt is sacrosanct. London, Oxfordshire and Nottinghamshire, as well as the wider South West region, are facing the biggest incursions.

“It isn’t good enough to plonk housing estates down on some huge greenfield site in the country where there are no transport links,” Lloyd Webber said. “I cannot believe that people out of choice want to live in some of these developments. Acres and acres without any real centre, car dependent totally. Absolutely insane. The CPRE’s warning shows that we desperately need a coherent planning vision for Britain.

“The average city has an awful lot of space that could be used better – not least the space wasted on car parking. There are ways of using and regenerating spaces within our towns and cities that brings them back to life and takes people off dependency on cars. Where there are empty high streets we should consider allowing former shops to be converted back to housing. Can’t we use the centre a bit more intelligently?”

On two recent visits to the cinema in his nearest town, Newbury in Berkshire, he found the surrounding streets dead and the cinema only 25 per cent full. “If it were one of my theatres, I would be suicidal”, he said.

Lloyd Webber is especially anxious about how development could wreck the “precious” relationship of cathedral cities with their surrounding countryside.

“Look what happened at Malmesbury Abbey. Whereas from the great Norman porch you used to look down on the countryside, you now look down on Tesco.”

He understands the need for more homes but says the Government’s 2012 decision to relax planning restrictions and introduce a bias in favour of ”sustainable development’’ looks like backfiring. “Unless there is a really coherent national policy that transcends the short-termism of successive administrations, we will end up with a vast urban sprawl and destroy the thing we love. This is an important as any issue the country faces. The built environment affects every single one of us and what we do in future generations.” However, although he gives me chapter and verse of a debate on the subject that he wants to introduce in the House of Lords, he is careful not to comment on the forthcoming election, claiming that politics ”bores’’ him these days.

Lloyd Webber would probably be a conservationist or an architectural historian if he were not already the biggest name in the history of musical theatre. He believes that encroachments on the countryside and crass decisions about listed buildings stem from delegating to local planners who no longer have experienced advisers on conservation and urban design and are not equipped to deal with the issues themselves. Some councils have dispensed with their conservation officers altogether or replaced them with private consultants with no local grounding. Not enough young planners are getting proper training because of their heavy workloads.

“It is a really vital issue: people are coming out of university without the knowledge and background to take certain planning decisions. Training is lacking.”

He recalls a ”professional’’ he encountered recently who claimed that timbers were from a ship dated 1560 when “We all knew that they were timbers that had been put in during an alteration made in 1950. You’re up against that.”

“I have never taken a penny out of the theatres”

Andrew Lloyd Webber owns six West End theatres and a half share in another, so his experience of professionals charged with enforcing listed building regulations – and the dilemmas that have to be resolved – is acutely personal. His passion is as much for preserving the glory of the buildings as filling them. “I have never taken a penny out of the theatres. Every penny they make goes back into the buildings. There are some people who regard theatre ownership as commercial. I am not one of them.”

He also knows at first hand, through his support of the annual Angel Awards, that the initiative of local people in rescuing their heritage needs an enlightened and sympathetic approach from local planners.

The Angel Awards were established in 2011 by Lloyd Webber and English Heritage and are supported by the Daily Telegraph. They celebrate those tenacious and visionary men and women who step in to preserve industrial buildings, churches, monuments or pubs without waiting for public bodies to act.

“There is a whole army of unsung heroes up and down the country who have pulled off extraordinary things,” says Lloyd Webber. “Without any form of help from institutions or governments, they have raised enormous amounts of money for the preservation of things they love and are of importance. A whole pot-pourri of weird and wonderful things have been restored against all odds. We should be celebrating people who are finding uses for buildings that are not longer fit for their original purpose”.

”We cannot take our heritage for granted”

Entries are being invited now for the 2015 awards. “We want them from absolutely everywhere,” he says. “Any heritage project qualifies. We cannot take our heritage for granted. Buildings are the most vulnerable of the arts. They are exposed to everything – the weather, people who don’t like them, the wrecker’s ball. When you write a piece of music, even if it doesn’t find favour at the time, at least you’ve got the score and somebody can dig it up in years to come.”

Andrew Lloyd Webber was 67 last month and in some ways there is a feeling that he’s retrenching. He says he’s stopped buying pre-Raphaelite art (his unparalleled collection was shown at the Royal Academy a few years ago) because the art world has gone has gone crazy. “They quote ridiculous prices I can’t afford. I’d have to sell to be able to buy. I say: ‘Dream on’.” For his birthday on March 22, he was delighted to be given three reissued vinyl albums. He thinks vinyl sounds better than digital music – “digital sound is at the moment pretty crude” – and loves “the physical thing of the record sleeve” with its artwork and libretto, just as he treasures the printed book over the electronic and believes it will survive.

Behind him in his London studio stand two 20-year-old Yamaha Clavinovas on which he wrote many of his musical hits. They remind him that his vast musical archive is going to present a conundrum. Even if it is deposited in the right storage conditions, the equipment required to play it is disappearing fast. “It [the digital piano] was one of the very first instruments on which you could record as you were going along and then go back over it. They have never made a better version for a composer. Now you cannot get the bits and pieces.”

”Everyone now wants to take cats”

He had a brush with cancer five years ago, and then a prolonged spell of chronic back pain but, though lean and nervy, is back to full-time production and composition. “I feel I’m making up for four lost years

His new version of Cats at the London Palladium, originally for 13 weeks and starring Nicole Scherzinger as Grizabella, has been extended for a further four. “It did three times better than we thought it would. Thirteen weeks at the London Palladium. I know that building and that’s almost impossible. It has kicked it off again all round the world. Everyone now wants to take the production. It has a new face and is seating a completely new audience. That’s very exciting to see.”

Cats will open in Paris this summer; Love Never Dies, his sequel to Phantom of the Opera is destined for Hamburg in September, while School of Rock, for which he has written ten songs and will be the producer, opens on Broadway in December. So should Cats follow on there in April or in the autumn? The question is, he says, how quickly can the company be expected to move from one big show to the other. “It’s a big ask for my small company to go straight in. I think we will lean towards the Fall. But it’s a lovely problem to have.”

• For more details on the 2015 Angel Awards visit www.historicengland.org.uk/angelawards. Deadline for entries is April 26.

• NOW READ THIS – Hands off our land: the lies and the laws of the land

Just when you think it can’t possibly get any worse, it does. Day after day for the past two and a half weeks, this newspaper has been publishing devastating revelations about the Government’s so-called planning reforms – disclosing, for example, that they were largely drawn up by developers; that, despite ministers’ assurances, they do threaten the green belt; and that they have already been quietly put into effect even though they are still draft proposals out for formal consultation.

But, believe me, there’s more – much more. For the further you look into the slim, 52-page draft National Planning Policy Framework that has caused all the fuss, and its accompanying documents, the more horrors there are. They contain more unexploded mines per square inch than the most liberally strewn battlefield.