The first walkout will last for two days and a second 48-hour strike is scheduled to begin at 3pm on Monday, as the Communication Workers' Union (CWU) and the Royal Mail remain in dispute over pay and modernisation issues.

The CWU has threatened to stage a series of rolling strikes every Monday until the dispute is resolved to its satisfaction, the BBC reported.

Meanwhile, HM Revenue & Customs (HMRC) is recommending that people make electronic rather than postal payments during the dispute.

It says this method is more efficient and more secure than paying by post.