The Environment Agency was accused of “stupidity and arrogance” after a senior official described its response to the flooding crisis as a “success story”.
It also came under fire from a Cabinet minister who attacked the quality of its advice and questioned the calibre of its leadership.
David Jordan, its director of operations, provoked the backlash after he defended its handling of the emergency which has left much of the Somerset Levels under water.
He acknowledged the “individual tragedies” of 5,000 families whose homes had been flooded.
But he added: “Also we need to recognise that 1.3m other properties would have flooded if these flood defences had not been built. That is the success story, if you like, that we are talking about. It does represent the benefit of investing in flood defences.”
Tory MP Ian Liddell-Grainger, whose Bridgwater and West Somerset constituency covers the inundated area, retorted: “This is getting worse. This is absolute stupidity and arrogance. This is a tragedy and disaster.
“The Prime Minister said yesterday it is a biblical scene, and he was right. It’s not a success story. This is an out of touch, out of control quango which is stuck in a time warp of arrogance and stupidity.”
The MP has previously denounced the Agency’s chair, Lord Smith of Finsbury, as a “git” and a “coward”. The peer, who is a former Labour Cabinet minister, had refused demands to resign ahead of July when his contract expires.
Eric Pickles, the Communities Secretary, admitted the Government had blundered by not heeding calls for rivers to be dredged to make them less likely to burst their banks. Farmers in Somerset asked Downing Street six months ago for dredging the rivers, but their request was turned down.
Mr Pickles said he apologised unreservedly for the mistake, but also took a swipe at the embattled Agency.
“We made a mistake, there’s no doubt about that, and we perhaps relied too much on the Environment Agency's advice.
“We recognise that we should have dredged and I think it is important now that we get on the process of getting those people back into their houses once we are able to really do some serious pumping.”
Mr Pickles also delivered a damning vote of no confidence in Lord Smith, saving he believed “parts” of the Agency had been well-led.
But Labour pinned the blame for the crisis on the Government’s “chaotic and slow” response to the flooding. Maria Eagle, the shadow Environment Secretary, said: “It is inexcusable it took so long to get the pumps, boats and sandbags to the communities that desperately needed help.”
The Green Party leader, Natalie Bennett, called for the replacement as Environment Secretary of Owen Paterson, who is currently recuperating from an eye operation.
“I think David Cameron really should be looking at whether he should have an Environment Secretary who has shown he doesn't grasp the reality of climate change,” she told Sky News.
She also said the Government and the previous Labour administration had not spent enough money on flood defences and the coalition's cuts to the Environment Agency should be reversed.
* Mr Pickles dismissed a “populist” call from Ukip and some Tory MPs for foreign aid spending to be diverted to British flood victims. He said the cash could be used to mitigate global warming with an effect on extreme weather in this country.