LONDON, May 21 (Reuters) - Britain's Royal Mail is to trial a Sunday delivery service for parcels as it looks to address growing demand driven by consumers ordering goods online.
Royal Mail, at the centre of a political storm over its privatisation, said on Wednesday it would trial Sunday parcel deliveries within the M25 motorway later this summer, extending its current six-days-a-week service.
Critics claim the government's sale of a 60 percent stake in the business last October short-changed the taxpayer.
Parcels make up almost half of Royal Mail's 9.15 billion pound ($15.42 billion) revenues and are the company's main focus for growth as letter volumes steadily decline due to the use of email and messaging.
Royal Mail's express parcels business, Parcelforce Worldwide, will also launch a Sunday delivery service in June for online shoppers through participating e-retailers, the firm said.
"Through these new Sunday services we are exploring ways to improve our flexibility and provide more options for people to receive items they have ordered online," Royal Mail Chief Executive Moya Greene said in a statement.
A pilot to open around 100 UK delivery offices on Sunday that handle its highest parcel volumes will also be launched, allowing customers more time to collect packages they had not been at home to receive.
The Communication Workers Union, which represents the majority of Royal Mail staff, welcomed the move.
"With ever-increasing numbers of people opting to shop online, Sunday services are necessary to deal with the growing demand in parcel delivery," CWU deputy general secretary Dave Ward said in a statement.
The CWU agreed a new deal over pay, pensions and working conditions with Royal Mail last December, having threatened to strike during the busy Christmas period.
Shares in Royal Mail, which is due to report its 2013-14 full-year results on Thursday, were up 0.3 percent to 571 pence at 0738 GMT in a slightly lower market.
$1 = 0.5935 British Pounds Reporting by Neil Maidment; Editing by Erica Billingham