NEWCASTLE, England — Lake-size puddles glimmer in low-lying fields. Corrupted floorboards and ruined furniture pile high on sidewalks. Far from New Orleans, this is the scene of Britain’s worst floods since 1947, which left three dead in July and are predicted to cost insurers up to $6.6 billion, according to Risk Management Solutions, an American-based catastrophic risk modeler with a European headquarters in London.

Observers’ early comparisons to Hurricane Katrina, which ravaged America’s Gulf Coast in August 2005, ultimately proved wildly disproportionate. Katrina left more than 1,400 dead in Louisiana alone and cost insurers more than $40 billion, according to the Insurance Information Institute. Yet as the last floodwaters drain away, one comparison to Katrina holds up: the peculiar distribution of political cost.

Just as Katrina boded ill for President Bush and his Republican Party, with critics accusing the federal government for falling far short in its emergency response, floods have left Britain’s top conservative politician stranded in a sea of criticism.

In the latest sign of crisis for David Cameron, the leader of the Conservative Party, one of the party’s biggest donors Tuesday said he was withdrawing financial support. Sir Tom Cowie said Mr. Cameron’s handling of the floods and other matters had left the party looking “arrogant.” “All I can say is I am very, very disappointed with the state of the party. I will not mince my words: I shan’t send them any more money,” he told the Guardian newspaper.

As the rain fell, a different outcome seemed likely. Prime Minister Brown and his governing Labour Party appeared susceptible to criticism, having reacted hesitantly to years of warnings from flood-defense experts at Britain’s Environment Agency. Mr. Cameron donned rubber Wellington boots and tromped through the neighborhoods of his submerged West Oxfordshire parliamentary constituency, where he offered praise for the “grit and determination” of ordinary folk, local journalists reported.

Mr. Cameron’s reward? Jeers in the national press and the most vigorous speculation yet over whether he can lead Britain’s biggest opposition party back to power after Labour’s decade of dominance, first under Mr. Blair and, since June 27, under Mr. Brown.

“As Gordon Brown’s bounce gets ever higher, Mr. Cameron appears to be cowering under the trampoline,” an article in the Daily Telegraph said.

After the floods, a poll published by Conservativehome.com — considered a key barometer of enthusiasm among grass-roots Conservative Party activists — found that confidence in Mr. Cameron’s potential to become Britain’s next prime minister had sunk precipitously, to less than 50% from 77% last January.

But the news is not bad only for British Conservative Party members. Britain’s summer floods offer the latest example of how right-of-center politicians can get battered by natural disasters.

Unlike Mr. Bush, bitterly criticized for staying far from hurricane-affected areas in the immediate aftermath of Katrina, Mr. Cameron plunged straight in. Yet after sloshing through floodwaters with Martin Ivens, a columnist for the Times of London, Mr. Ivens mocked him as “Dead-in-the-water-Dave.” Similarly negative assessments rang throughout the British press.

The flood damages sustained by Mr. Cameron stemmed in part from his decision to keep a foreign trip on his schedule, a whirlwind visit to Rwanda that invited accusations of aloofness.

Yet Mr. Cameron got plenty wet before he flew to Kigali, and he returned soon thereafter to his constituency. A deeper explanation for the Conservative leader’s woes flows from his decision to focus on flood victims’ resilience. By emphasizing private initiative over the government’s role, Mr. Cameron held true to his party’s ideological foundations, but he bypassed what party loyalists saw as an opportunity to criticize the government — a common charge.

“Pick up a newspaper and it is full of this administration’s failures, most of them directly linked to Brown’s role when chancellor. Yet the Conservatives are not calling the prime minister to account,” Michael Portillo, a Conservative former government minister, wrote in the Times of London.

Mr. Brown, who for the past decade as chancellor managed Britain’s purse, has so far polled well as prime minister. Yet Mr. Cameron faces an immense challenge in re-engineering Britain’s political climate, in part because the weather literally might be against him.

In contrast to the Bush administration, accused by critical European governments of too slowly embracing the politics of climate change, most British officials — Mr. Cameron and much of his Conservative Party included — have done so vigorously. Releases of statistical data from the Met Office — the government’s weather bureau, which is part of the Ministry of Defense — are routinely embroidered with warnings about climate change.

For example, a Met Office press release issued at the height of the floods on July 26 described the record level of rainfall seen between May and July before concluding with a note that “we all need … to meet the challenges posed by climate change.” Similarly, an earlier Met Office press release issued after this year’s unusually dry, hot April described record average temperatures that month within the context of “temperature rise … being experienced on a global scale.”

The dry, hot April had earlier yielded predictions of a dry, hot summer and long-term projections of a “Mediterranean” climate for Britain. The exceptionally wet, cool summer that has followed has not dashed such expectations. Peter Stott, a Met Office climatologist, folds the apparently contradictory phenomena into a unified global warming hypothesis. “With a warmer climate, there could be an increase in extreme rainfall events despite the expected general trend toward drier summers,” he said.

Nigel Lawson, a Conservative former chancellor under Margaret Thatcher, the former prime minister, is one in a small but determined chorus of voices that has noted with growing concern the politicization of Britain’s weather.

In a speech last year at the Center for Policy Studies in London, seen as an important address by British skeptics of global warming, Mr. Lawson warned that the country’s climate change politics increasingly resembled that of “primitive societies” in which “it was customary for extreme weather events to be explained as punishment from the gods for the sins of the people.”

Under such circumstances, an opposition leader who declined to lodge meteorological complaints against his opponents in government might be charged with timidity or disengagement — precisely the charges that Mr. Cameron now faces.