Time has proved I was right all along, says Prince Charles as he defends 40 years of outspoken ideas

• Charles said critics accused him of wanting to go back to the 'Middle Ages'
• He said we have 'chucked nature out the door' over the past 100 years
• The Prince claimed that after 40 years some of his ideas are now 'appealing'

By Darren Boyle

Prince Charles has said you need to 'stick to your guns' even if people do not think you are 'sensible' as after 40 years you may be proved right all along.

In his first major interview for five years, Charles spoke at length about many of the issues which have caused him controversy in the past such as architecture, the environment and the economy.

During the interview, Charles said he had been heavily criticised over some of his views on how to develop a sustainable community.

Prince Charles said that after 35 or 40 years some of his ideas are finally 'starting to appeal to people'

He told the Financial Times: 'I was accused of going back to, I don't know what, the Middle Ages. Extraordinary when you think about it. All the volume house builders said it couldn't be done. They wouldn't be able to sell their houses next to people on the lowest incomes. But it has worked and I think that approach has helped to add social as well as environmental and funnily enough, commercial value.'

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The Prince used the example of the Poundbury development on Duchy of Cornwall land outside Rochester. A one bedroom apartment in a central location in the town costs just £135,000 while four-bedroom houses are on sale for £610,000. He said he wanted to demonstrate how a good, well planned development can help improve people's lives.

'The problem in my case is what I was trying to suggest 35 years ago or something 40 years ago, wasn't considered, I suppose, as anyway sensible whatsoever. I don't know. Anyway, it wasn't very easy, but if you stick to your guns, sometimes 35 years later, whatever it is, you suddenly find that some of these things are starting to appeal to people.'

The Prince used the example of Poundbury, which was developed on Duchy of Cornwall land near Rochester, pictured, on how good planning can add social, environmental and even financial value

He added: 'All that's been going on for the last 100 years is that people, have just chucked nature out the door, which is coming back to bite us and kick us in the teeth, big time. What I have been trying to remind people for the past 40 years is that you can't operate an entire conventional system, whether it's economics, business or the way we live and surround ourselves, what we eat, without recognising that there are severe negative externalities that are not being accounted for.'

The Prince, it has emerged this weekend, tried to influence Tony Blair's government to increase the number of grammar schools.

According to  BBC Radio 4 documentary, The Royal Activist, Mr Blunkett said: 'I would explain that our policy was not to expand grammar schools, and he didn't like that.

'He was very keen that we should go back to a different era where youngsters had what he would have seen as the opportunity to escape from their background, whereas I wanted to change their background.'

Prince Charles, pictured here in the passenger seat of an Aston Martin, warned that for the past 100 years 'we have just kicked nature out the door' and it would 'kick us in the teeth'

Mr Blunkett added: 'I can see constitutionally that there's an argument that the heir to the throne should not get involved in controversy; the honest truth is I didn't mind.

'If you are waiting to be the king of the United Kingdom, and you've waited a very long time, you genuinely have to engage with something or you'd go spare.'

CONTROVERSIAL PRINCE CHARLES

• Discussing the proposed extention of the National Gallery in May 1994 he said: 'What is proposed is like a monstrous carbuncle on the face of a much loved and elegant friend.' As a result of the intervention, planners decided to go with an alternate design
• Prince Charles converted his Highgrove Estate to organic in 1986. He said: 'In many ways the garden at Highgrove represents one very small attempt to heal the appallingly short-sighted damage done to the soil, the landscape and to our own souls.'
• Former Government Minister Michael Meacher said Prince Charles tried to quietly influence government policy on climate change and GM crops. He said: 'We were together in trying to persuade Tony Blair to change course.'
• In 2003 Prince Charles called on the Royal Society to investigate threat posed by nanotechnology and the possibility of it turning the world into 'grey goo'. He was ridiculed at the time but food companies want to use the technology to create beer that won't go flat, low-fat mayonnaise that tastes like the real thing and food that can stay on the shelf for longer.

Former environment minister Michael Meacher said he and the Prince 'would consort together quietly' to affect policy on climate change and genetically modified crops.

'I knew that he largely agreed with me and he knew that I largely agreed with him,' said Mr Meacher.

'We were together in trying to persuade Tony Blair to change course.'

Another former Labour cabinet minister, Peter Hain, said they shared an interest in complementary medicine.

'He had been constantly frustrated at his inability to persuade any health ministers anywhere that that was a good idea, and so he, as he once described it to me, found me unique from this point of view, in being somebody that actually agreed with him on this, and might want to deliver it.'

Mr Hain added: 'When I was Secretary of State for Northern Ireland in 2005-7, he was delighted when I told him that since I was running the place I could more or less do what I wanted to do.

'I was able to introduce a trial for complementary medicine on the NHS, and it had spectacularly good results, that people's well-being and health was vastly improved.

'And when he learnt about this he was really enthusiastic and tried to persuade the Welsh government to do the same thing and the government in Whitehall to do the same thing for England, but not successfully.'

The Prince's policy interventions were supported by former prime minister Sir John Major, who said: 'I think it is encouraging that the Prince of Wales is entirely free from his unique perspective to write to ministers or the prime minister in a way that is invariably intended to be helpful, and I think to cut that off, or to make sure those letters are much more bland than they otherwise might be, would be a loss.'

Sir John also revealed that he occasionally changed policy as a result of discussions with the Queen - although he would not be drawn on the specific times this took place.

Asked if he remembered being influenced by the Queen, Sir John said: 'I think every prime minister can think that, and can think of occasions where that happened...

'But the answer is yes of course. It would be very foolish indeed not to be influenced.'