People will continue to eat unhealthily, even when healthy foods are affordable and accessible, a new British study has found.

Researchers from England and Scotland found that trials of supplying health foods to communities deprived of access to such items have disappointing results.

The study, published in the British Medical Journal, concluded that improving the supply of affordable healthy foods - one of the cornerstones of strategies drawn up in Westminster and Holyrood to fight obesity - is not enough. It said that people need to have their diets and food buying habits influenced by a long-term programme of health education.

A spokesman for the BMJ said: "What we have concluded is that the entire issue is a little like taking a horse to water - you cannot make it drink."

A study in Newcastle showed knowledge, affluence and lifestyle rather than retail provision determined dietary habits.

Another pilot to improve access to healthy foods in Leeds found positive changes in fruit and vegetable consumption, while a similar study in Glasgow found little evidence for an overall effect.

One researcher said: "There is no evidence thus far that just improving access to healthy food changes dietary habits in any meaningful way. We have to improve education as well."

However, a government spokeswoman told The Scotsman that schemes to offer affordable fruit and vegetables are working. She said: "We know that change can only happen when individuals take action themselves. Our responsibility is to create the conditions where disadvantaged people feel able to make healthier choices.

"The pilot schemes have shown that projects can increase the consumption of fruit and vegetables in those groups who have the lowest intake of these foods by an average of one portion a day."