For the purposes of an equal pay claim, can a woman compare her pay and conditions with those of any man?

No. Under the Equality Act 2010, a woman's comparator must be a man employed on "like work", "work rated as equivalent" or "work of equal value". In addition he must be employed by the woman's employer or an associated employer, and work at the same establishment as her or at a different one where common terms and conditions apply. The comparator may be the woman's predecessor in the post, but cannot be her successor. A woman cannot rely on a hypothetical comparator unless she is claiming direct sex discrimination in pay and her case falls to be dealt with under s.71 of the Equality Act in that a sex equality clause or rule has no effect because she does not have a male comparator (in this situation, she may be able to rely on her successor as a comparator).