The second UK postal workers' strike in five days has seen thousands more walk out at Royal Mail as well as at the Post Office and telecoms giant BT.
Communication Worker's Union General Secretary Dave Ward said that 170,000 staff across the three companies were out on strike on Wednesday over a raft of issues, including below-inflation pay offers and alleged plans to sell Royal Mail off to a foreign firm.
The BBC reported that 40,000 staff at BT – formerly British Telecom – and its infrastructure division Openreach had walked out, with the balance on strike at the privatized mail carrier. The broadcaster said 115,000 postal workers were out in last Friday's strike.
Strikers picketing the Royal Mail delivery office in the northeast London suburb of Debden were serenaded by two of their comrades.
Ward told the BBC that Royal Mail's "blatant lies" had been exposed, repeating his claim that the firm was in "secret talks" with a "private equity investment group" in Luxembourg for a takeover.
He said the plan was to turn the 500-year-old public service into "another gig economy" business – like Uber taxis and Deliveroo takeaway food riders.
The union leader said his members had already agreed to provide Sunday service, which Royal Mail accused them of blocking.
Royal Mail in turn said the CWU was jeopardizing its members' jobs and future pay rises by striking.
"The CWU's self-centered actions with the wider trade union movement is putting jobs at risk, and making pay rises less affordable... making Royal Mail's future more uncertain than at any time in its long history," a company spokesperson said.