Image caption Royal Mail's parcel delivery business provided almost half of group sales

Royal Mail's annual profits have more than doubled, helped by strong growth in parcel deliveries as more people shop online.

Operating profits for the 52 weeks to the end of March jumped to £403m, up from £152m for the previous year.

Its core UK parcels and letters unit reported an operating profit of £294m, compared with just £33m last year.

The strong results come ahead of the firm's expected privatisation next year.

"The transformation of Royal Mail is well underway," said Royal Mail chief executive Moya Greene.

'Well positioned'

Revenues from UK parcel deliveries were up 13%, and parcels now account for 48% of revenue across the group.

On a like-for-like basis, the volume of parcels sent rose by 5% over the year.

The rise in parcel deliveries is in marked contrast to a sharp fall in UK letter deliveries, which fell by 8%. Despite the fall, revenues rose by 3% due to the increase in stamp prices.

Royal Mail said it was still the biggest overall parcel delivery player by revenue.

"We remain well positioned to benefit from significant growth in online retailing in the UK," added Ms Greene.

Ms Greene also emphasised that external capital was key to the continued transformation of Royal Mail's fortunes.

The coalition government has said that it plans to privatise the UK's national postal service by March next year.

Business Secretary Vince Cable has now suggested that a flotation could come as soon as the autumn.

When asked on BBC Radio 4's Today Programme if his favoured option was to float the business on the stock market in the autumn, he replied: "Well that's the one we are looking at - but we have an open mind."

However, union action has presented a potential stumbling block. The Communication Workers Union, which represents the majority of Royal Mail's staff, is considering industrial action.

And The National Federation of Sub-Postmasters, which represents thousands of post offices, says it has "serious concerns" over the plans.