What are the rules for divers?
If you are a diver working in the UK continental shelf, then you are taxed under a different set of rules, as if you were self-employed. You are able to claim expenses against your gross income as if you were self-employed. Class 1 NI is deducted and therefore this makes you exempt to paying class 4 NI.
If you are a Diver working out of the UK continental shelf, then this income is classed as employed income, and as such, would be able to claim foreign earnings deduction on this, should you have had sufficient time spent out of the UK to qualify. (see FED.)