The Conservatives have called for an investigation into attacks on firefighters after the Fire Brigades Union (FBU) claimed incidents were four-times more prevalent than Whitehall admits.
Union leaders warned attacks on firefighters risk becoming a "recreational activity"
The FBU estimates its members suffer an average of 40 attacks a week, ranging from verbal abuse to physical harm.
According to the union, there were 1,500 assaults last year, up from 1,300 in 2006. But Whitehall claims incidents fell from 1,300 to 400.
This places the number of attacks on crews in England and Wales at four-times government figures. While the FBU claims attacks rose by 15 per cent last year, the government reports they were down 68 per cent.
Shadow communities secretary Eric Pickles called for an urgent review into the government's "dodgy figures".
He said: "Ministers must come clean and explain why they are hiding or failing to record the rising number of assaults on firefighters."
Mr Pickles called for the "full force of the law" to be used against those that hinder or harm firefighters.
FBU general secretary Matt Wrack expressed disbelief that firemen and women can be attacked while trying to save lives.
"In some areas attacking fire crews has become a recreational activity with very serious consequences," he said.
The union argues crews should be better trained to deal with attacks and supported through extra investment.
Some crews have already been kitted out with "spit kits" to collect DNA and CCTV has been installed on engines in Greater Manchester.