Kenyan ministers have reacted angrily to comments by the British high commissioner to Kenya accusing the government of "massive looting".
Sir Edward says he underestimated the corruption
"Sir Edward Clay has just behaved as an enemy of this government," Justice and Constitutional Minister Kiraitu Murungi told Kenyan state radio.
Meanwhile the vice-president said Kenyans did not need to be dictated to by foreigners.
President Mwai Kibaki came to power in 2002 promising an anti-sleaze crusade.
But Kenya - ranked 122 out of 133 countries in a corruption survey by Transparency International in 2003 - has been repeatedly criticised by donors for not doing enough to tackle corruption in high places .
Sir Edward also made headlines last year, lambasting Kenya's failure to tackle graft.
Mr Murungi said the government would file a formal protest to Britain about Sir Edward's "extravagant statements" and he questioned the high commissioner's timing.
"What he is saying is not very new; a lot of corruption... took place during the previous regime. We did not get a word about it from the British High Commission."
According to Vice-President Moody Awori, the government's fight against corruption was continuing, but needed more time.
"We are going to use our own home-grown methods, not anybody else's," he said.
Sir Edward's comments come a month after John Githong'o, a senior government anti-graft adviser, warned that efforts to prosecute those accused of corruption were meeting resistance from powerful interests in the administration.
"We are not talking about minor corruption," Sir Edward said in speech at Kenya's Journalist of the Year awards on Wednesday.
"We are talking about massive looting and/or grand corruption which... has a huge impact on Kenya's economy."
"People outside Kenya... manipulate people inside Kenya, near to or actually in the government, with an ease and confidence which is frightening."
Last July, Sir Edward accused unnamed corrupt officials of behaving "like gluttons" and "vomiting on the shoes" of donors.
He said he did not regret his words and he had underestimated the scale of the problem.
Following the allegations the government said it had fought corruption by sacking corrupt police officers and forming a department of ethics and good governance.
It summoned Sir Edward to "give facts and figures and to name names".
Awori says investigations into sleaze take time
He has since given a dossier to the Kenyan president that he says details corruption and fraudulent procurement worth hundreds of millions of dollars.
He said those suspected of involvement in corruption, including government ministers, should be removed so that investigations are not hindered.
"If the herdsman... finds a leopard has entered the boma [homestead], he will first eject the leopard before seeing what damage it has done," the British envoy said.
"He cannot... hope to assess the damage while the leopard is still there."
Donors, who stopped lending to Kenya under previous President Daniel arap Moi, reopened cash channels under Mr Kibaki.
But they have criticised the lack of progress and threatened to cut off funds once more.
One of the recent scandals involved a deal for the Kenyan government to buy equipment from a front company.
The project fell through before $41.5m could be handed over. No one involved in the scam has been prosecuted.