Fiona Reynolds: 'It's thanks to the National Trust that Britain doesn't look like New Jersey'

The overhaul of UK planning laws has one big opponent – and her four million members, writes Michael McCarthy

Until Fiona Reynolds brought the subject up, I had never considered why the English countryside of today doesn't resemble New Jersey, as an endless sprawl of shopping malls, gas stations, light industry and huge advertising hoardings, wooden or neon but all garish, along every major road between town A and town B.

Dame Fiona says: "There's an edge, where the town stops and the countryside begins." And she adds: "You see large areas of agricultural land that aren't full of scattered developments, and it's so different from much of the rest of the world."

The point the director-general of the National Trust is making is that in England, indeed in Britain as a whole, we still have a countryside worthy of the name, a countryside that feels green and rural and unspoiled enough to inspire us, not semi-invaded by the town. But we nearly didn't.

For in the 1920s, the same development pressures that brought ubiquitous urban sprawl to America were working here, as uncontrolled "ribbon development" spread along every highway, with the Great West Road out of London providing what some thought was a nightmarish glimpse of the future.

The nightmare future didn't happen because a group of visionary conservationists sounded the alarm. Dame Fiona knows them well – "People like Clough Williams-Ellis, the architect, who wrote [the essay] England and The Octopus in 1927, GM Trevelyan who wrote a pamphlet called Must England's Beauty Perish?" Most were associated with the National Trust and the fledgling Council for the Protection of Rural England (CPRE), and what they did was create a climate of opinion in which the most powerful mechanism possible for safeguarding the countryside was eventually brought forth: the planning system.

The Town and Country Planning Act, 1947, stopped sprawl in its tracks. It established the principle that a contained settlement would be the norm, with definite boundaries, and that with any development, a conscious decision would be taken about where was the best place to put it. The result? We are not like other countries. "The planning system has given us a countryside that we can be proud of, and it's given us the productive capability of the countryside as well," Dame Fiona says.

"I mean, agricultural land is still committed to being in agricultural use and not ripe for speculative development, in one of the most densely populated countries in the world – which is quite extraordinary, actually, when you think of the pressures on the land area."

And now, after more than 60 years of its service, the Government is taking the spanners to the planning system, taking it largely to bits, all in the name of economic growth – and in the opinion of the National Trust, throwing the baby out with the bathwater. The new National Planning Policy Framework, unveiled last summer for consultation, now decrees that the default answer to any development proposal will be Yes.

It scraps the principle of building on brownfield land before greenfield land. It abandons the recognition that ordinary, undesignated countryside has value and should be protected. And in reducing 1,000 pages of planning guidance to a document 52 pages long, it changes the entire system, the Trust believes, from a tool to protect the landscape, to a tool to foster growth – or, as other critics have phrased it, a developers' free-for-all.

When this was unveiled last July, the Trust immediately challenged the Government and orchestrated an immense wave of opposition which put ministers on the back foot and may yet force a retreat. It was a most unusual move for Europe's biggest conservation charity, normally fully occupied looking after its 600,000-plus acres of land, its 700-plus miles of coastline and its 300-plus historic houses. It does not normally engage in political campaigning – for example, it had hardly anything to say about the proposed sell-off earlier last year of the public forest estate.

But the planning reforms, Dame Fiona says, constituted "an exceptional circumstance that struck at the very heart of the Trust's core purpose" (which is officially defined as "to promote the permanent preservation for the benefit of the nation of land and buildings of historic importance and natural beauty").

And once it entered the fray, the Government began to blink. It wasn't the Trust's lands and coastline and historic houses that gave it pause; it was the four million members – four million voters from the heart of Middle England.

First Greg Clark, the Planning Minister in charge of the reforms, who had accused the Trust of "nihilistic selfishness" in its opposition, was obliged to soften his stance. Then David Cameron wrote to the Trust, insisting on his own personal commitment to the countryside. And eventually Mr Cameron agreed to meet Dame Fiona – on 15 November – to hear her concerns. (She refuses to comment on the meeting, but a source says it was "pretty frosty".)

Now she is waiting, like everyone else, for the revised framework document – due some time in the next few weeks – to see if the Government will give ground on the proposals. Their principal progenitor is the Chancellor, George Osborne (they were first outlined in his Plan for Growth in last year's Budget), who says the changes are essential. But Dame Fiona is optimistic. "I'm hopeful that our points have been heard, and we will get something better," she says.

A Cambridge geography graduate, engaging and naturally friendly, she is 53 and married with three daughters, and has run the Trust for 11 years with signal success, increasing membership by 50 per cent (it was 2.7 million when she took over) and making it more "welcoming", which others might see as removing any trace of stuffiness it once had. She was as qualified as anyone to spot a mortal threat to the planning system and its ability to safeguard the countryside, as she has worked with it throughout a stellar career in conservation – first as secretary of the Council (now the Campaign) for National Parks, then as director of the Council (also now the Campaign) for the Protection of Rural England.

She came to the Trust after a two-year interlude as director of the women's unit in the Cabinet Office in the early years of the Blair government, which caused the Daily Mail to label her one of "Tony's cronies" – which she says is "complete nonsense". She was hired by the Civil Service and took the job to gain experience of policy-making at the highest level, and is not a member of any political party.

But she understands politics. She knows that the stakes with the National Planning Policy Framework are high. And though she has discreetly ended campaigning until the final document is published, if it makes no changes, the Government can expect to hear from Dame Fiona again – with four million voters from Middle England at her back.

A LIFE IN BRIEF: Dame Fiona Reynolds

Born 29 March 1958, in Alston, Cumbria. Married to Bob Merrill, a trained teacher and learning mentor, with whom she has three daughters.

Education Went to school in Rugby, Warwickshire, before gaining a first class BA Hons degree in Geography and Land Management at Newnham College, Cambridge, and following that with an MPhil.

Career Joins the Council for National Parks in 1980, then spends five years as assistant director of the Council for the Protection of Rural England (CPRE) followed by six years as its director, from 1992 to 1998. Became the Director of the Women's Unit in the Cabinet Office until 2000, before taking over as Director-General of the National Trust in January 2001. From 2001 to 2002 served as a member on the Policy Commission on the Future of Food and Farming. Was awarded a CBE in 1998 and appointed a Dame in 2008.

History: planning regulation

1946 The New Town Act is passed. The ambitious programme would build new towns across the country (including Stevenage in 1951, right) with the government designating areas for new settlements.

1947 The Town and Country Planning Act repeals all former legislation and sets the framework for all modern planning legislation. It is consolidated in the 1990 act of the same name.

1955 A Government circular formalises the security of "green belt" land, a planning tool first available to local authorities in London in 1938. It urged local councils to consider designating green belts where they wanted to restrict urban growth.

1998 The Labour government sets a target of 60 per cent for new homes to be built on brownfield land, regarded as "previously developed land".

2011 After the announcement of the National Planning Policy Framework (NPPF), published in July 2011, the National Trust set themselves up in staunch opposition. A breakthrough of sorts comes in September 2011 when David Cameron writes to the Trust reassuring them that the environmental benefits of developments would be assessed before planning decisions were passed.