I get asked from time to time about the various aspects of hot food planning regs, VAT implications, licences and so on. So for Johanne Hole and Raj Lal who both recently emailed me, here is what I know about this decidedly woolly subject.

Premises are either A1, which is retail, A3 (takeaway) or A5 (café). It is easier to go down than up, so if you are A1, it is hard to go up to A3 (which is why Tesco is buying up all the pubs: it is easy to go down in usage).

The so-called 25% rule which says you can do hot food so long as it accounts for no more than 25% of your turnover is merely a rule of thumb, although is accepted by many.

I had a long conversation with Matthew Parish, technical manager at Country Choice, the bake-off specialists. Matthew has fielded questions of this sort and untangled more confusing regs than he's had hot dinners.

Generally speaking, says Matthew, if hot food is not your primary purpose, it can be done from A1 premises so long as if you took the hot food away the business wouldn't fail. Bakeries, he adds, are classified as A1, as are sandwich bars. Both can sell soup and hot pies, but move on to burger bars, kebabs, and fish and chips and you are in A3 territory. And that brings other considerations such as planning permission for hot food licences, extraction fans and noise pollution.

"The best way to look at it," says Matthew, "is a supermarket with a café. Take the café away and the supermarket will still survive. It's considered inconsequential business."

Councils will often wag their heads if they try to put two ideas together. You're a c-store therefore you open late. And you want to sell hot food? Tch, the noise, the mess, the parking

But most councils won't need telling if you are putting in a simple bake-off (take your supplier's advice). Country Choice has 6,000 customers and only a fraction have encountered any obstacles.

You might want to tell the environmental health officer though. The EHO will no doubt say: "Bread is it? No problem." But if you are buying in the raw chickens to roast then expect more visits from them.

For any of you not doing hot food, have a look at the margins. They're tasty.