British Prime Minister Tony Blair faces the most grueling test of his political career today as a judicial inquiry begins investigating the death of David Kelly, the scientist central to claims Blair's government exaggerated the case for war in Iraq.

Over the next two months, a long series of witnesses will be called to a bland-looking room attached to the Royal Courts of Justice in central London to give evidence that could potentially damage Blair's reputation beyond repair.

Among those due to be called before senior judge Brian Hutton, heading the inquiry, are a string of government officials, ministers and – eventually - Blair himself.

Already yesterday, an unofficial political truce in place since Kelly was found with a slit wrist near his home in Oxfordshire, southern England, just over three weeks ago appeared to be unravelling.

The run-up to the government weapons expert's suicide highlighted a "culture of duplicity and deceit" in Blair's government, charged a senior member of the opposition Conservative Party.

The country had "a prime minister who's a stranger to the truth and a government that's rotten to the core," finance spokesperson Michael Howard said.

Kelly's death came after he was identified as the main source for a highly contentious BBC report in May claiming Blair's staff exaggerated intelligence data on Iraq's weapons of mass destruction ahead of the US-led war.

The weapons expert was revealed as having briefed Andrew Gilligan, a BBC radio reporter who alleged that the government deliberately "sexed-up" a dossier last September on Iraq's weapons.

Blair was the United States' closest ally in the war to unseat Saddam Hussein, launched in March, and repeated claims that he duped a sceptical nation over the case for the conflict have caused him severe political damage.

The veracity or otherwise of the intelligence about Saddam's alleged illegal weaponry will not come under the remit of Hutton's inquiry, which was officially opened on August 1.

Nonetheless, the possibility that ministers or officials deliberately tried to deflect attention from the weapons row by starting a war of words with the BBC - culminating in Kelly's death - would be almost as damaging.

Blair was yesterday coming under fire from all sides.

"The latest crisis for the government stems entirely from its obsession with presentation over substance," said Peter Kilfoyle, a lawmaker from Blair's ruling Labour party.

Menzies Campbell, a senior member of the opposition Liberal Democrats, predicted that the inquiry could shape the country's political future.

"The reputation of the prime minister and his government rests in the hands of Lord Hutton," he said.

Blair - currently on holiday in Barbados - is considered very unlikely to lose his job immediately.

However one of his most trusted ministers might not be so lucky, according to reports yesterday.

Defence Secretary Geoff Hoon was being lined up as the government's "fall guy" for allegedly authorising the identification of Kelly as the source for the BBC story, the Sunday Express said.

"He (Hoon) is going to be hung out to dry in the hope that his resignation will get Tony Blair off the hook," an unnamed government source was quoted as saying. – Sapa-AFP.