If you’re a contractor working through your own limited company and are outside the scope of IR35 then expenses allowable against your income is straightforward Revenue and Customs rules state that expenses can be claimed provided they are wholly and exclusively for the purposes of your business.
HMRC will allow expenses such as: Company formation fees, Accountancy fees, Business travel and Accommodation, Postage, Stationery, Telephone calls, Employer’s N.I. contributions, Salaries, Subscriptions, Insurance, Contributions to an executive pension plan, Business entertainment etc.