Royal Mail is facing a probe from communications regulator Ofcom after it admitted failing to deliver nearly one in four First Class items on time.
Britain's postal service said only 76.5 per cent of First Class letters and parcels arrived within one working day, including Saturdays, in the year to March 2025.
The target for First Class post - the price of which has just risen five pence to £1.70 for a standard stamp, the sixth hike in three years - is 93 per cent.
However, it failed to even meet this target after two working days, with 92.3 per cent arriving within that time frame.
It also delivered 92.2 per cent of Second Class mail within the target of three working days after collection, short of the 98.5 per cent target.
