Royal Mail postal workers have begun a new 48-hour strike today in an ongoing dispute over pay and conditions.
115,000 members of the Communication Workers Union (CWU) have walked out in one of the biggest industry walkouts the UK has seen, with university lecturers and sixth-form staff also taking action.
Picket lines are being held outside postal delivery and sorting offices as well as schools and universities.
It comes as industrial unrest continues to spread across the UK in rows over pay, conditions and job contracts as the cost of living soars.
Postal workers walked out on Thursday and Friday last week, and another wave of strikes is planned in the run-up to Christmas - on 9, 11, 14, 15, 23 and 24 December - a crucial trading period for businesses.
The Communication Workers Union (CWU) says it wants a pay rise that matches inflation - which is currently 11.1%.
Royal Mail has given an offer of a 9% pay rise, however, the offer includes changes to Sunday working, start times and flexible working.
The company claim these are necessary changes so it can “re-invent and compete in the growing parcels market”, like Evri or UPS.
CWU general secretary Dave Ward said: “Postal workers want to get on with serving the communities they belong to, delivering Christmas gifts and tackling the backlog from recent weeks.
“But they know their value and they will not meekly accept the casualisation of their jobs, the destruction of their conditions and the impoverishment of their families.”
It comes as postal workers claimed that parcels are being prioritised over letters as the strike continues.
One anonymous member of staff told BBC Wales: “First thing management will say is ‘no overtime allowed and just clear your parcels and leave all the mail’, so that can mean you’ll have half a job left on the deck.
“This week I’ve had a hospital appointment [letter] on my round that has been there for two days.”
The Royal Mail denied this and have urged the CWU to call off strike action.
A spokesperson said: “Royal Mail does not operate a policy of prioritising parcels over letters. Every item of mail is important to us. We regularly remind colleagues that the delivery, collection and processing of letters and parcels should be treated with equal importance.”
"The CWU is striking at our busiest time, holding Christmas to ransom for our customers, businesses and families across the country. We apologise to our customers and strongly urge them to post early for Christmas.
“We are proud to have the best pay and conditions in our industry. In an industry dominated by the ‘gig economy’, insecure work, and low pay, our model sets us apart and we want to preserve it. Despite losing more than £1million a day, we have made a best and final pay offer worth up to 9%.
“Strike action has already cost our people £1,000 each and is putting more jobs at risk. The money allocated to the pay deal should be going to our people, but it risks being eaten away by the costs of further strike action.”
A report in The Telegraph claimed that the company has resorted to using the Ryde app to hire gig economy workers to deliver items while staff are on strike.
The publication said that job adverts were posted on the app, which is used by delivery companies like Evri, for workers to "complete deliveries using the Ryde app and Royal Mail vehicles".
The CWU has tweeted: "Royal Mail Group are using ‘Ryde’ app to recruit couriers to break the strikes tomorrow and Thursday.
"Do you think now is a good time to reveal we have hundreds of people signed up for shifts tomorrow and none of them will be turning up?"