It's just a thought, but I wonder why.........

We in Britain continue to have a tax structure which makes it advantageous to build on "green-field" sites, rather than reclaimed "brown-field" sites.

We in Britain have VAT, a tax which penalises the refurbishment and restoration of old buildings, over the building of new buildings. It is often more cost effective to demolish an old building and replace it with a new one, than to restore it.

We (worldwide) continue to build structures in concrete which will have probable lifespan of less than a century, yet concrete is one of the most carbon expensive building materials available. One ton of cement manufactured puts an incredible one ton of carbon into the atmosphere. It is also a difficult and carbon extravegant material to dispose of at the end if the structure's lifespan. Concrete buildings are also inherently more difficult to repair than a traditionally built structure as they deteriorate.

We in Britain have wonderfully detailed and comprehensive building regulations, yet don't equip, as standard, every new building with solar panels. If the market for solar panels was to increase, the unit cost would fall - as is the case with all technology; digital watches, pocket calculators and PCs, for example.

We in Britain have no tax incentive to use zero-sulphur and carbon neutral vegetable diesel over fossil diesel. With farming in a degree of crisis, oil-substitute and bio-mass crops might go some way to aleviating two problems.

We in the energy hungry west (though, increasingly worldwide) don't invest in helping financially poor, but sun-rich, countries develop the infrastructure to produce solar electricity for export.

We in Britain don't build new industrial sites and supermarkets in situations where a rail link might be feasable either now or in the future.

We in Britain have the option to buy low energy electrical items, yet why are high energy equivalents available more cheaply? A shift in costing bias would encourage greater use of the energy efficient, the resultant increased manufacture of the energy efficient items would in turn lead to a cost reduction through economy of scale.

We in Britain have a farming community in difficulties, and a desperate need to produce a carbon-low or neutral fuel. Why aren't we producing more vegetable oil as a carbon-low diesel substitute? We could never produce enough to replace fossil diesel completely, but even if we grew 5% of our diesel this would be a step in the right direction. Yet bio-diesel remains extremely difficult to source.

We in Britain can travel the length of our country by air (the most carbon expensive mode of transport) for a fraction of the cost to make the same journey by rail (potentially one of the least carbon expensive).

We in Britain choose to regard railways as a hopeless catastrophe and increase our dependence upon roads (and increasingly, air travel). Railways lend themselves to electrification in a way that no other form of transport can - and electricity is the most easily produced renewable form of energy. Plus, the geographical "footprint" of a mainline railway track is approximately one third that of a motorway. Railway bridges, for example (for bridges are cost and carbon expensive items) need only be one third of the width of a motorway equivalent, and a bridge crossing a main-line railway line needs to be only about a third as long as its road equivalent. Obviously we cannot manage without a modern and efficient road system, but maybe we ought to attach equal importance to our railway system. For example, if I want to send a parcel from Leominster to Ludlow, there is no facility for doing so by rail, even though it is the next rail stop up the main line; I'd have to carry it as passenger hand luggage.

Britain was once criss-crossed with railways, in the 1950s and '60s much of this infrastructure was demolished as car ownership became increasingly affordable and widespread. As a nation we are now much more mobile than we were in the 1960s - far more of us travel (and travel further) to work, and our need for cheap (subsidised, if neccessary), available, efficient and comfortable public transport is greater than ever. Similarly, goods are moved further and in vastly greater quantities than ever before. Interestingly, much of that rail network which was discarded is still extant and where appropriate, given the will, could be resurrected. Were one to consider building a railway line from Leominster to Worcester via Bromyard (a well used commuter trip in all directions), for example, it would be quite a bonus to discover that all of the line's levels have been surveyed and probably 80% of the cuttings and embankments (along with several bridges) are already in place. Guess what? They are.

............as I say, it's only a thought, and I'm sure there are lots of simple answers.