* CWU says court hearing on Nov. 12
* Last Royal Mail national strike was in 2009
* Delivery of domestic parcels, letters could be hurt (Adds analyst comment, parcel volumes)
By Noor Zainab Hussain
Nov 8 (Reuters) - Britain's Royal Mail will go to court next week to block a potential strike by its biggest union, due to be held around the time of the national election on Dec. 12 and in the traditionally busy run-up to Christmas.
Royal Mail said on Friday it would apply for an interim order from the UK High Court, stating it believed the strike ballot had been unlawful, as it seeks to avert the first national strike by its workers in a decade.
The CWU last month voted by 97% in favour of a nationwide strike, saying the company had failed to adhere to a pension deal agreed last year. Royal Mail said it had honoured the deal.
The union has not given exact dates of when a strike could take place, but Royal Mail has said the planned strike could affect deliveries of postal votes in the election and Christmas deliveries.
Amazon UK lists Royal Mail as one of its carriers. As well as delivering online shopping, Royal Mail handles letters from children addressed to Santa Claus around the holidays.
"Royal Mail have made an application to take us to the High Court. They claim there are irregularities with our ballot. We clearly refute this and will be represented. A hearing will possibly be on Tuesday," the CWU said in a tweet on Friday.
The CWU on Monday rejected an offer from Royal Mail.
The company has told the union that if it removed the threat of strike action for the rest of 2019, the company would enter talks without preconditions. CWU in turn called Royal Mail's offer a "stunt" which the union would not fall for.
It would be the first national postal strike since thousands of workers went on strike in October https://uk.reuters.com/article/uk-britain-royalmail/second-wave-of-postal-strikes-starts-idUKTRE59R4DK20091029 2009, creating a massive backlog of undelivered letters and forcing Royal Mail to hire temporary staff to cope with the strike and the Christmas rush.
In 2017, Royal Mail blocked a strike by the union, winning a High Court injunction preventing action during the crucial pre-Christmas delivery period.
In February last year Royal Mail and the CWU reached an agreement to end a nearly 10-month dispute over plans to replace the firm's defined benefit pension scheme - the agreement the union now says the company has not adhered to.
LETTERS TO SANTA
Royal Mail's daily delivery service of letters and parcels in the UK could be affected by strike action as the service forms the bulk of the company's business, which also includes e-commerce operations. Parcelforce Worldwide, Royal Mail's express courier parcel service, has been excluded from CWU's ballot.
The election could be affected as postal votes accounted for around 18% of votes cast in the last election in 2017, according to figures from the Electoral Commission.
Royal Mail handled 164 million parcels in the December trading period last year, according to a company statement.
Jefferies analyst David Kerstens said that although Royal Mail's court application might delay industrial action, it is unlikely to solve the labour dispute.
A strike could come at a time when Royal Mail faces the threat of renationalisation from the opposition Labour Party, which also plans to return utilities and train companies to public ownership.
Royal Mail made its London market debut https://uk.reuters.com/article/uk-britain-royalmail-results/royal-mail-profit-soars-before-privatisation-idUKBRE94K0CG20130521 in 2013 - at the time Britain's biggest privatisation for 20 years. The CWU had been extremely vocal in its opposition to the privatisation. (Reporting by Noor Zainab Hussain and additional reporting by Pushkala Aripaka in Bengaluru; editing by Patrick Graham and Susan Fenton)