Sainsbury's currently has the largest choice of organic food

Its findings explain why more and more retailers are trying to cater for this sort of demand.

Tesco will announce on Tuesday that it is re-packaging its organic goods and substantially increasing its range.

It wants to ensure they are available in every single store in a bid to become the biggest seller of organic products in the UK.

Tesco also says - as do all the big supermarket chains - that it is ploughing in money to help support the UK organic movement.

Natural foods

Currently, around 70% of everything sold in UK stores as organic is imported.

To the delight of the Prince of Wales - whose commitment to "natural" foods used to be lampooned as cranky - Tesco has struck a deal with his organic food company, Duchy Originals, to stock more of its products, such as the organic bread and biscuits.

This will be worth almost �100,000 to the Prince of Wales Charitable Foundation, which takes all the profits from Duchy Originals.

Prince Charles is a well known fan of organic food

And if all that were not enough, the retailer is also sponsoring a professor of organic ecology at Newcastle University.

So, according to Tesco, organic food no longer has just a niche market; it is mainstream.

The supermarket giant's move follows a year of dramatic developments in the organic food market.

The sector is growing at 40% a year in the wake of food scares and concern about genetic modification.

Last June, Iceland was credited with bringing organic products to the mass market for the first time.

It captured the mood of the moment and announced an �8m investment in food produced without the use of artificial chemicals.

No more expensive

It says all its own brand frozen vegetables will be organic by next month - and they will be no more expensive than the non-organic versions.

Tesco says it is spending �5m on bringing down the prices of its own brand organic fresh produce.

It acknowledges the goods will continue to be more expensive than non-organic products since it costs farmers more to produce organic food.

But the store insists the gap between organic and non-organic is beginning to close - even if only by a small amount.

Asda boasts that it will offer the best value organics around - some 10% to 15% better than competitors on an average basket of organic products.

But the supermarket chain that currently has the largest selection of organic products - Sainbury's - seems to be taking the highest moral high ground.

It says that if an item costs more to produce than a non-organic version, then the customer will have to pay the difference.

Sainsbury's says it is not about profiteering and it is not about unfair premiums - it is simply about paying the right price for the right product.