...depends on what agreement there is with the Company's tax office.
At GO Captains get £20 and F/O's £12 per sector, 30% of which is taxed at their marginal rate (usually 40%).
Sector pay is almost always more lucrative than duty pay, is easier to understand and calculate, and offers a greater incentive to turn up for work, particularly at a company such as Ryanair where sector pay is quite substantial.