Yes you do, and you also need to tell your local council food safety officer what you are planning to do.
You will need to have your kitchen inspected and one of the things they stipulate is to have two sinks so that hand washing etc is kept away from food preparation.
I hope your venture is very successful!

Thank you that's really helpful. I will contact them tomorrow. x

A food safety officer is going to want to see your business and food service permits. Also think about permit fees, licensing fees, taxes for this, taxes for that, insurance for this and insurance for that....figure all the aforetomentioned into your overhead and project how much you would have to sell just to break even and if you have enough capital to keep your infant business going for at least three months before you turn a profit. Then decide if it would be worth your time and trouble. I'm talking about this from an across the pond point of view but when you have a business it's going to seem like everyone is trying to put the squeeze on you. Another thought would be to sell your goods to small eateries such as tea rooms, coffee shops, gourmet shops, even beauty salons who serve their clientele snacks. Good Luck!

Astrantia even if as Loosestrife suggests you don't sell your products direct you will still need to do as Stera says and if you have young children or pets you will find it difficult to meet the standards required in order to produce food for sale in your own kitchen. This is a huge can of worms and I suggest you take a look at this website before you do anything else:

http://www.food.gov.uk/business-industry/caterers/startingup

At one time you could simply have started cooking and selling, not now though. The scope of this question is way outside the knowledge of most GoYers, myself included. My son is a professional chef running three messes and I know just how many pieces of paper he has to hold.

I used to sell through Womens Institute markets (now Country Markets or something similar). The WI can give lots of advice.