Royal Mail workers are to vote again on strikes in a long-running dispute over job security and conditions.

The Communication Workers Union (CWU) has formally served notice on the company for a national ballot.

READ MORE: Royal Mail says outlook 'challenging'

Voting papers will be sent out on March 3, with the result due two weeks later.

The union secured a huge mandate for action last year but the Royal Mail staged a successful legal challenge to halt strikes.

There was a 97 per cent vote in favour of industrial action on a turnout of almost 76 per cent.

However, the company successfully argued there were irregularities in the ballot.

CWU general secretary Dave Ward said: “Our members are solidly behind their union and will return a massive yes vote in this ballot.

“The company have the opportunity to take up our offer of serious negotiations prior to any action being taken.

“If they don’t then we will see the first national postal strike in over a decade.

READ MORE: Royal Mail workers vote in favour of strikes amid dispute

“We will not stand by and see our industry, the service we provide to businesses and the public and our members jobs destroyed.”

The new ballot involves around 111,000 Royal Mail workers and 4,500 at Parcelforce.