There has been concern expressed by postgraduates at a few institutions that studentships earning in excess of £7,000 per year from a Research Council studentship will have income tax deducted from their pay. To set the record straight, this is not the case. Studentships are expressly exempt from income tax, and anyone who wants to read official confirmation can check out:
However, as new EPSRC grants are now paid through University payroll departments, they may not have realised this and deducted tax from pay anyway. If you find that your University has done this, make sure you inform them of this straight away, and let NPC know too.