Blair addresses US Congress

There are new tensions between the two leaders

UK Prime Minister Tony Blair is addressing the United States Congress at the start of a visit to Washington, dominated by Iraq and the Middle East peace process

After his speech, Mr Blair and US President George W Bush will hold talks.

Mr Blair has been urged to push Mr Bush for two UK terror suspects held at Guantanamo Bay to be returned to Britain for a possible trial.

The father of Moazzam Begg, one of the men being held, told the BBC on Thursday that Mr Blair must convince President Bush they would get a proper trial in the UK.

Mr Blair's visit comes as an audiotape message purported to be from ousted Iraqi leader Saddam Hussein accused the US and Britain of fabricating arguments for invading Iraq.

Other British leaders to address US Congress: Margaret Thatcher Winston Churchill Clement Attlee

The tape, broadcast on the al-Arabiya television station, calls for further attacks on US-led coalition forces in the country and condemns Iraqis who co-operate with the occupying powers.

The row over the use of British intelligence is likely to overshadowed much of Mr Blair's visit.

Uranium dispute

The UK and US have been divided over allegations made by the British Government that Saddam Hussein was trying to buy uranium from Niger.

Mr Bush mentioned the British claims in his State of the Union address - but the US now says the claims should not have been repeated.

MPs want Blair to exert pressure over the Guantanamo prisoners

Mr Blair stands by the allegations, saying they were based on more than what the UN's nuclear watchdog branded as forged documents.

More than 200 MPs have called for Mr Begg and Feroz Abbasi, who are due to face US military tribunals, to be repatriated.

Mr Begg's father, Azad, told Radio 4's Today programme that his 35-year-old son would die unless he was returned to the UK and that he had been deprived of human rights while in US captivity.

He said Mr Blair must assure the US that "this country is the mother of the democratic world with the oldest legal system in the entire Western world, internationally accepted as a fair and objective legal system".

Scepticism about the intelligence on Iraq has begun to lap around Mr Bush's feet as well Paul Reynolds World affairs correspondent Iraq's effect on US-UK ties

The US Congress had been expected during the visit to present Mr Blair with its highest civilian honour for his "steadfast" support of America "during a very trying and historic time for our two countries".

But the presentation of the Congressional Gold Medal has been postponed, reportedly because it has not been minted yet.

On Wednesday, Mr Blair faced rowdy scenes over the continuing weapons row in his last prime minister's questions before Parliament's long summer recess.

The House of Commons foreign affairs committee last week reported that the "jury is still out" on the case for war in Iraq.