Royal Mail was unlikely to meet postal delivery targets for the year, said Adam Crozier, chief executive, and could incur a hefty customer compensation bill as a result.

Royal Mail said that 92.1 per cent of first class letters arrived the next day between July and September, missing regulator Postcomm's target of 92.5 per cent. This was an improvement on the previous quarter's figure of 88.3 per cent.