In a statement, the postal operator said: “We apologise for the inconvenience the CWU’s industrial action will cause to our customers and the public.

“Royal Mail has well-developed contingency plans to minimise customer disruption, and keep people, businesses and the country connected. The contingency plans are focused on getting mail delivery back to normal as quickly as possible after strike action.”

It said that on days when strike action is taking place, it will deliver as many Special Delivery and Tracked24 parcels as possible, it will prioritise the delivery of Covid test kits and medical prescriptions wherever possible, and it will not be delivering letters, with the exception of Special Delivery.

The organisation advised customers to post their items as early as possible in advance of the strike dates, continue to post items at post boxes or Post Offices – although collections will be less frequent on strike days, and to visit Royal Mail’s website for the latest detailed information on services.

“Immediately following strike action, Royal Mail will lift the suspension of letter deliveries and prioritise the delivery of critical government mailings and NHS letters,” it added.

Over 115,000 union members voted to strike over pay, with the other strike dates set for 31 August, and 8 and 9 September. Last week, workers then voted in a second ballot by 98.7% on a 72.2% turnout to enter into formal dispute with management over pay and conditions.

Separately, the group has launched a new leadership programme which it said will help ambitious managers achieve their full potential by equipping them with the skills needed to meet changing customer demands.

The Diamonds Programme is aimed at developing a diverse set of leaders from across the business with a focus on nurturing their emotional intelligence, confidence, and operational capabilities.

The postal operator said the move is designed to ensure it has access to a talented pool of leaders as the company transforms into a more parcels-focused business.

The company stated: “Successful candidates will embody the company’s values while being able to navigate and influence a fast-changing business with confidence. They will benefit from targeted development assessments, career guidance and tailored support, to help them grow as leaders and deliver an ambitious programme of change as they progress to more senior roles in the business.”

The programme will include a development assessment that helps managers understand their strengths as well as areas in need of development, a feedback and coaching session from a trained facilitator to help tailor a plan that will support their career development, coaching sessions aimed at building capability in key areas for the business, and access to mentoring schemes with a more experienced leader to assist in navigating their onward career journey.

Around 70 staff were selected to join the leadership programme’s first session at Royal Mail’s training academy in Daventry, Northamptonshire.

Royal Mail said the programme represents a significant investment in its workforce and will help the business accelerate its transformation in a competitive market.

Zareena Brown, chief people officer at Royal Mail, said: “Through our academy, we are investing in our people to create the next generation of leaders at Royal Mail.

“Our new leadership programme has been specially designed to ensure our managers have the right skills to support Royal Mail’s ongoing reinvention and generate sustainable growth across the business. I am pleased to welcome the first cohort of managers onto the programme.”

The academy, which was officially opened in June 2022, is based at Royal Mail’s new Midlands Super Hub. When operational next year, the facility will process more than one million parcels a day.

Employees can also access the academy virtually digitally and ‘on the job’. It is supported by five new satellite learning centres in Edinburgh, Warrington, Bristol, Gatwick, and Oxford.

Royal Mail said it invested £6m in training in 2021-2022, equating to around 23,000 training days, compared to 19,000 training days the previous year.