Hi my daughter will be studying in London this fall. We're trying to determine an appropriate monthly food budget in GBP. She will be able to cook in her dormitory and I would appreciate any ideas on a reasonable amount of money. Thanks!

she needs to be clever with her shopping, using supermarkets not convenience shops and using their value ranges.
there are supermarkets right throughout London, even in the centre.
Teach her how to cook (if she doesn't know how), she'll save a phenomenal amount of money even if she can do the basics. Investing in some lessons from mom + the odd student cook book (search Amazon) would be a big help. If she's a veggie, she could trim that £200 a bit, say 20-25% or so perhaps.
Dear rest of UK posters; please vote with your costings...

£200 per month sounds a bit steep for a student, but depends on what they eat, you could easily eat at home for £20 week. But it depends if you are on a budget, obviously for eating out a couple of times a week add to that.
As well as supermarkets, you will find cheaper meats at for example brixton market, chinese shops are much cheaper for things like noodles, soy sauces ect.

If you are a really careful shopper, then I would have thought £200 was more than adequate, even allowing for London prices. There have been programmes on UK tv about whole families trying to live on £50 per week, though clearly the quality of food is low at this sort of rate. All supermarkets have their "value" ranges and £50 per week / £200 per month should be OK.
As for Fwoggie's suggestion about £200 per month going out money, well I'm now speculating on the sort of student he must have been!
#6 I was allowing not just for nights out, but for sightseeing, day trips to Oxford/Brighton/Cambridge etc, possibly a weekend in Paris, that sorta thing. If you dial back for nights out only, you could probably chop it in half.
I was a bit of a party animal to be fair.

I don't live in London but I do cook only for myself and on buying food for cooking alone I spend only about £60-70 a month. I shop in Aldi's which is great for cheap (but tasty!) food and the cheapest fruit and veg compared to other supermarkets. I eat well and don't just live on pasta / baked beans / toast etc.
On top of this, I do eat out probably 5-6 a month, so that adds up, and I won't compare those prices to London eating out prices. However, I think that it would be perfectly within reach for someone to live for far less than £200 for their food shopping alone. Maybe a bit more than £60-70 a month in London, but definitely lower than £200 if the shopper is savvy and doesn't waste food either. A lot of money spent on food is wasted because we don't eat it in time and it goes off. Freezing portions of meals / bread etc all helps save money.
Correct me if I'm wrong??

I live in London, and spend about £260 a month for 2 of us. We are vegetarians, and don't have wildly expensive tastes, but we buy what we want. We don't live in central London, so have access to large supermarkets - the central London versions (Sainsburys local, Tesco express) tend to be more expensive. £200 for one person seems a lot to me.