How much should I budget for groceries in London?

£40 to £50 per week if you are going to buy and cook fresh food with plenty of fruit, vegetables and other healthy raw ingredients, and that is worth doing to stay fit and well. Organic food is widely available at the better supermarket chains like Sainsburys
and Waitrose and is obviously far healthier for you

There's no set number because it depends hugely on what you decide to eat - if for example you want to eat expensive foods you'll spend a lot more than if you budget and eat little meat/fish. Some students spend almost nothing by living entirely of noodles.

Think about what you might buy now. The budget'll be similar.

Let me be the first to say: it entirely depends. Do you cook? How well? Do you mind living off noodles, sauce, and tuna? Are you gonna demand fresh vegetables with each meal? Where are you going to shop? Waitrose? Expensive. (Though, do avail yourself of the membership program since members get free coffee each time they visit.) Tesco? Considerably cheaper. The reason why the school is being vague is because everybody's food needs are different and it's impossible to generalize.

If you're from the US, be prepared for a bit of sticker shock. Food is expensive in the UK in comparison - I particularly remember being absolutely thrown by the price of tomatoes and milk. (The UK is not the best place to be if you're a milk drinker.)

I'd budget at LEAST 20-30 pounds a week if you're budget-conscious, and are willing to put the effort into cooking. You could do it for cheaper, but then you're getting into tuna-pasta-a-lot territory.

Lidl is a good low budget supermarket, but if you're living in London you're spoiled for choice when it comes to restaurants and some of them are good value (e.g buffet style places in Chinatown)

depends on what do you buy as a food
shop in Iceland and sainsbury cheapest and good markets