THE Royal Mail has revealed a drop in half-year profits. The company spooked investors with its warning that the UK parcels market will grow by much less than expected over the next two years due to the impact of Amazon's increased use of its own network for deliveries. A year on from its controversial flotation, Royal Mail's shares have slumped by 30 per cent from a peak in February. As well as facing fierce competition in its parcels division, Royal Mail repeated its warning that the way rivals such as TNT are given access rights to delivery routes threatens its commitment to the six-day a week Universal Service. Pre-tax profits fell to £218 million from £233m a year earlier in the six months to September 28.