Bullock is among the UK's leading tax practitioners with more than 20 years of experience advising in relation to large and complex disputes with HMRC for large corporates and high net worth individuals, including in particular leading negotiations and handling tax litigation at all levels from the Tax Tribunal to the Supreme Court and European Court of Justice. He advises in relation to the powers of HMRC and the application of those powers in enquiries and investigations and has advised FTSE companies, professional advisory firms and professional bodies in relation to the exercise of such powers. He has acted in landmark Judicial Review cases relevant to HMRC.