The Government was accused today of failing to fulfil a promise to strengthen the law on dangerous dogs despite continuing attacks against members of the public and workers.
The Communication Workers Union (CWU), which represents postal staff, said the Government promised to make an announcement before the Easter recess, which started last week, but had "broken its word".
More than 23,000 postal workers have been attacked by dogs over the past four years, while many members of the public, including children, have also been the victims of attacks.
CWU general secretary Billy Hayes said: "How many more tragedies will it take for the Government to stop the irresponsible shilly-shallying of the past two years since David Cameron gave us an assurance in 2010 that he would act. His words have proved to be empty."
The union pointed out that the Scottish and Northern Ireland governments and Welsh Assembly had all changed the law to crack down on irresponsible dog owners.
The CWU is pressing for the law to be changed to cover attacks on private land, where most incidents involving postal workers take place.
The Royal Mail launched an inquiry into dog attacks last month to study issues such as the law.
More than 4,000 working days have been lost over the past year because of attacks on postal workers, costing the Royal Mail around £400,000.
Almost 400 postmen and women have taken time off sick since last April after being attacked by dogs.