If you are truly self-employed (which has clear definitions in HMRC speak) you can indeed do this. Amongst the criteria are that you have some control over when you do the work (start / finish) and that you have several customers - not just one. If you are self-employed you get paid gross and have to complete an annual tax return on which you state your expenses. You then get assessed for tax and employees NI on your profits.
Amongst things you would be able to claim for are, are all materials used and tools, mileage for getting to the jobs (because your normal place of work will be your home).
You need to register with HMRC as self-employed - there is more info here.
http://www.hmrc.gov.uk/selfemployed/