Unilever CEO Paul Polman has called for radical changes in the system of food production, in order to meet the demands of the world’s rapidly growing population.

Speaking at the City Food Lecture at London’s Guildhall last night, Mr Polman said that “stresses and strains” – including the recent floods in Pakistan and Australia – have called into question the resilience of the global food system.

“Based on UN projections, there will be 3bn extra mouths to feed by 2050, which equates to 70% more food than we’re currently producing,” he said, before going on to outline four core proposals to tackle the dilemma:

l The widespread adoption of sustainable farming practices;

l Government commitment to investment in agriculture;

l The removal of “market-distorting subsidies and incentives”;

l The freedom to trade without barriers.

More than half of Unilever’s raw materials come from agriculture, putting food security high on the company’s agenda, but Mr Polman’s hard line on government subsidies was disputed by panel member and MD of The Co-operative Farms Christine Tacon.

“It is difficult to justify being in farming without our £2m subsidies payment – but don’t think for a minute that farmers in the UK like being subsidised,” she said.

Another member of the panel, editor of The Grocer Adam Leyland, stressed that consumers have their own part to play in the issue of food security, and must be prepared to see prices rising.

“Consumers have to recognise that the food industry represents extraordinary value. It’s an easy story to understand: the population is going up and a finite resource is becoming more scarce. It’s not a hard sell to say food prices are going up.”

Mr Polman used his final few minutes on the podium to rubbish “agro-pessimists”, arguing that there is plenty to be positive about – not least Unilever’s ambitious plans to source 100% of its raw materials from sustainable sources by 2020.

“The challenge is great, but I’m optimistic that we have what is needed to feed the ever-increasing population. Lots of change is needed, and lots can be done to stimulate this change.”

The lecture closed with a speech from HRH The Princess Royal, who praised Unilever for “sticking their necks out with the issue of food security”.