The fire service is being "crippled" by cuts in the number of control room staff, a report claims.
The Fire Brigades Union said more than 500 posts had been axed across the UK since 2010 - a quarter of the total.
The loss of so many jobs had led to "chronic" shortages, with staff having to work overtime, said the union.
More fire services are introducing 12 hour shifts, which is disruptive to family life, especially as most control room operators are women, the FBU said in a report.
Lynda Rowan O'Neill, of the FBU, said: "Control staff have been subjected to more than a decade of failed government policy, characterised by cuts, mergers and underinvestment."