Victoria Summerley: Town Life

I spent a happy half-term in Cornwall, visiting the Lost Gardens of Heligan. I returned to find an e-mail from the Royal Horticultural Society inviting me to a forum on the Lost Gardens of the South-east (and probably the South-west, too).

The forum's not really called that, of course. It's called, "What Future for Urban Gardens: Eden or Extinction?". The RHS wants to discuss the paving-over of front gardens, and the issue of back gardens being classified as brownfield sites.

A furore over the latter has been raging for most of this year, ever since the Conservatives accused John Prescott of "fiddling" planning guidelines to meet a government target that wanted to see 60 per cent of new development taking place on brownfield sites.

What's to debate, you might ask. It seems a straightforward issue. Let greedy builders get their mitts on our backyards - urban oases and havens for wildlife? You must be mad or bad. Ergo, John Prescott is bad or mad. Or both.

Read a few Tory websites, and you'll find similarly emotive language: "Jacqui Lait has slated secret plans by Deputy Prime Minister, John Prescott to concrete over the gardens of suburbia ... and to use council-tax payers' money to do it." And: "East Devon MP Hugo Swire this week pointed to new evidence that John Prescott is planning to concrete over back gardens across East Devon and the country."

When one finds oneself wanting to side with the Tories, it's time to look very carefully at the evidence. So, what's the truth about these "secret plans"? How could anyone describe the manicured lawns of suburbia as "brownfield"? The case so far seems to run like this:

The Government, as we all know, is keen to provide new housing, particularly affordable housing. It doesn't want to build on the green belt. So it is encouraging developers to build on brownfield sites. According to Planning Policy Guidance Document 3 (PPG3), this is anything which "is or was occupied by a permanent structure (excluding agricultural or forestry buildings)".

You can now see how - insane as it may sound - back gardens came to be classed as brownfield sites. When did John Prescott "surreptitiously" classify them as such? The Tories say that PPG3 was drafted in 2000. But, according to Baroness Andrews, Parliamentary Under-Secretary, Department for Communities and Local Government (DCLG), in the House of Lords on 10 May 2006, this policy - not legislation, but guidelines - was simply a reiteration of advice that had been in existence since 1985, when (I seem to recall) a Conservative government was in power.

Be this as it may, most people feel uneasy about the idea of gardens disappearing under piles of bricks and mortar. So, why not have legislation protecting them, such as the Tory MP Greg Clark's Protection of Private Gardens Bill (chucked out for the third and final time on 20 October)?

The trouble is, as a spokesman at the DCLG pointed out, it's very difficult to disentangle a house from its surrounding garden. At the moment, building a kitchen extension or conservatory is a fairly straightforward exercise, from a planning point of view. If gardens were ring-fenced by legislation, or classified as greenbelt, it might become difficult to remove a blade of grass without encountering yards of red tape.

Of course, in some cases that might be quite a good idea. You don't need any planning permission at all to concrete over your own garden. Yet the Royal Society for the Protection of Birds draws a direct link between this practice and the disappearance of garden birds - particularly sparrows, which in London have declined by 70 per cent in 10 years.

However, we would need very sophisticated policy-making indeed to get round all the potential pitfalls. Is that beyond the wit of our legislators? It would mean less in the way of emotive language, and more in the way of reasoned discussion. With luck, there will be lots of that at the RHS Forum.

The RHS Forum 2006 is on 8 November, at 5pm, at the Purcell Room, Royal Festival Hall, London. Tickets £7.95 RHS members, £9.95 non-members: 0845 612 1253