The possibility of a London-wide strike at Royal Mail grew this week after bosses refused to back down from plans to slash jobs at offices around the capital.
'The cuts have not been agreed with the union and therefore break a series of national agreements,' says Merlin Reader, a CWU union rep at London's Mount Pleasant mail centre.
'That's why we voted to demand a ballot across the city at the London Division union meeting.
'It's important that we all stand together on this. Otherwise they will pick us off one by one.'
There are signs that Royal Mail's cost-cutting agenda is also being pursued in many other parts of Britain. There are reports of ballot requests from areas as far apart as East Anglia, Durham and parts of Scotland.
Many union activists believe that there is a concerted attempt to slash jobs and weaken the union in the run up to the government's proposed privatisation of Royal Mail.
The CWU's London newsletter describes in detail a plan to introduce a Dutch-style postal system in which 84 percent of jobs will become part-time and hundreds of delivery offices will be closed.
TNT runs the Dutch postal service. It is the company tipped to buy a chunk of Royal Mail.
But there are signs that if the union is prepared to take determined action, it can beat off the bosses, the government and the privateers.
Postal workers in Bristol called off their strike ballot this week after Royal Mail retreated from attempts to implement cuts without union agreement.
However, some within the union worry that any strike action during the run-up to the parliamentary vote on privatisation could lose the union public support.
Others, such as Watford CWU secretary Alan Walsh, disagree. 'Opposition to post privatisation is massive,' he says. 'We've been running stalls in our town centre and each time we are mobbed with support.
'Now we are delivering thousands of postcards in the constituency of our local Labour MP, who has decided not to sign the union's Early Day Motion against the sell-off.
'The idea that public support would drain away if we took action against this is simply not true. The vast majority will understand that we are standing up for jobs and services.'
The CWU's postal executive was discussing the ballot requests as Socialist Worker went to press.