Prescott's big idea

John Prescott's Masterplan is to build 120,000 new homes eastwards along the Thames Gateway deserves a cautious welcome.

The Evening Standard has long campaigned for the provision of affordable housing for key London workers driven out of the capital because of the high cost of living.

If it will mean that London retains more high quality teachers, nurses and police officers, so much the better. Mr Prescott's critics argue that he should somehow halt development in the South East and build instead in depressed areas of the North. It is to his credit that he has resisted the temptation towards dirigiste social engineering in a way that would be doomed to failure.

London and the South are where people want to live. However, this is a major undertaking - and the first of an even bigger plan that might see as many as 700,000 new homes in the South East.

We have yet to be convinced that Mr Prescott has thought through all of the consequences. Above all it is unclear whether along with the additional housing, there will be developed the essential infrastructure in schools, hospitals, reservoirs and transport, to make the scheme viable.

In particular, the first part of the proposals, announced yesterday, depends upon building Crossrail, as an essential transport link eastwards beyond Woolwich. The Transport Secretary, Alistair Darling, has approved that scheme in principle, but, crucially, has not earmarked any money for it. That does not suggest there has been joined up planning for this venture.

Also, Mr Prescott must make it categorically clear to developers that a condition for all planning consent must be that the Green Belt is untouched. The Green Belt must be preserved not just for the sake of Londoners who need to breathe, but for the communities who live inside it.