There have been renewed calls for a tax on biscuits, sweets and cakes, as research revealed that fruit and vegetables have tripled in price in the past three decades.

A study by the Overseas Development Institute found the cost had increased in high-income countries and also in emerging countries such as Brazil, China, South Korea and Mexico.

The study found that, in 1980, fresh green vegetables cost the equivalent of 8p per 100g in 2010 prices, rising to 23p in 2012.

The report said: “A strong case emerges for using taxes and subsidies to offset these changes to encourage more consumption of healthy foods and less of unhealthy items.”

Commenting on the study, Tam Fry, of the National Obesity Forum, told The Times that food taxes were urgently needed.

He warned: “It can’t be on junk foods as these are the energy-dense foods on which huge numbers of people rely. But biscuits, sweets, cakes and so on — all that, I’m afraid, is indulgence. If you were to put a big tax on that, it would send a strong message.

“If it doesn’t happen then we’re going to see an escalation and pay more on treating the problem that results. Obesity and its related diseases will bring down the NHS.”

Peter Wareing, principle food safety advisor, Leatherhead Food Research will be leading a roundtable discussion on ‘Innovating to safely reduce salt, fat and sugar’ at New Frontiers in Food & Drink. The event, organised by British Baker, in conjunction with The Grocer, Meat Trades Journal and Food Manufacture, takes place in London on 26 June. For tickets see: www.newfrontiersinfoodanddrink.co.uk

The subject of sugary products, particularly bakery, has been in the headlines over the past six months. Here is an interactive timeline of some recent coverage: