Firefighters from brigades across the UK will stage a rally and lobby of MPs today to warn of the "savage" impact of Government spending cuts on jobs and safety.
Members of the Fire Brigades Union (FBU) will travel to London for the Westminster event, claiming that up to one in nine jobs are at risk.
Leaders of other unions as well as Labour MPs will speak at the rally, which is expected to attract thousands of firefighters.
Matt Wrack, general secretary of the FBU, said: "Over 7,000 people a year are rescued by frontline firefighters.
"Today's FBU event aims to highlight how Government spending cuts threaten to undermine this highly-valued frontline service and galvanise support against cuts.
"Savage cuts are looming if the Government persists in slashing budgets.
"The Comprehensive Spending Review set out plans to cut the capital grant to local fire authorities by 25% over four years.
"This grant accounts for around half of spending on the fire and rescue service overall, but up to two-thirds in metropolitan areas where more firefighters work. The rest comes from council tax.
"The FBU estimates the capital grant cut alone would mean over 7,000 firefighter jobs axed - more than one in nine firefighters."
The union warned that the impact on public safety would be "stark", with threats to crewing levels, fire cover at night and response times.
Mr Wrack said the planned cuts were "complete lunacy", adding that further attacks on jobs, pensions and shift systems were expected.
Firefighters in London have staged two strikes in a row over new shift patterns and only called off a walkout on Bonfire Night at the last minute so that fresh talks could be held.