A house as a deeded gift?

I have a small house in UK that I would like to sign over to my step daughter as a deeded gift. If she sold the house would she be responsible for capital gains tax?

Yes she would.
The Tax man is a B@$t@rtd

I take it this house is not your main residence? If you give her the house, and it is NOT your main residence, YOU will be liable for CGT. Even if no money changes hands, the market value of the house is taken for CGT purposes if a property is transferred.
If she later sells the house, she would be liable for any gain in the value of the property for the time she has had it.
If the house is your main residence, you wouldn't be liable for CGT, but unless you paid her the full commercial rent for the time you live there (on which she would pay tax) the value would be clawed back into your estate when you die. If she divorced, or you fell out with her, you could also find yourself homeless. Find a good financial advisor, and take his advice. Think about a Trust.