Royal Mail is set to purchase same day-delivery firm eCourier as it looks to strengthen its presence in the rapidly growing sector.

A spokesman for Royal Mail said there would be no job losses as a result of the deal, and there was no decision yet on whether eCourier would operate under its own brand or be incorporated into its own courier business, Sameday.

Royal Mail did not reveal what it paid for eCourier, but said the "financial terms of the transaction were not material in the context of the group as a whole".

The privatised service said the acquisition of the same-day firm, which operates mainly in London but offers nationwide distribution, would help expand its presence in one of the fastest-growing segments of the market.

eCourier chief executive Ian Oliver will remain in his role following the deal.

It comes as Royal Mail faces increasing pressure in the competitive parcel sector.

Over the summer, it revealed that growth in its parcels arm had been hampered by Amazon, which is increasingly moving deliveries on to its own network.

Royal Mail is due to deliver its half-year results tomorrow, with analysts predicting a six per cent fall operating profits to £327 million.

Speaking about today's deal, Royal Mail chief executive Moya Greene said: "Today's announcement marks another milestone in our strategic objective of increasing our presence in growth areas of the parcels market. Same-day deliveries are already one of the fastest-growing segments of the UK parcels market."