FILE PHOTO: A Royal Mail postal worker stands in the yard of a sorting office in Altrincham, Britain October 12, 2017. REUTERS/Phil Noble/File Photo

(Reuters) - Britain's Royal Mail RMG.L on Thursday confirmed that its biggest union lost an appeal to overturn a High Court injunction to stop a strike ahead of a general election and the holiday season next month.

The Communications Workers Union (CWU) lodged an appeal with Britain’s High Court last week after the former postal monopoly won the injunction to avert the first national strike by its workers in a decade.

“Royal Mail is pleased that the Court of Appeal has upheld the High Court’s decision... meaning that no industrial action can be taken before the completion of a lawful ballot”, Shane O’Riordain, Managing Director of Regulation and Corporate Affairs said.

The union separately confirmed in a tweet here that its appeal had been dismissed.

Royal Mail reiterated that it wanted to find a way to reach an agreement with the CWU.

In its half year results last week, the FTSE-250 company warned that it was running behind schedule with planned reforms as it grappled with the threat of the potential strike and a slowing UK economy.

Royal Mail, which employs more than 140,000 people in the UK, has been embroiled in a legal dispute with the CWU since September over a strike that would disrupt operations at its busiest time of the year.

The CWU did not respond to a request from Reuters for further comment.