Buckingham Palace has strongly rejected "outrageous" claims by a Labour MP that officials tried to warn David Cameron against appointing former News of the World editor Andy Coulson as his director of communications.
The Palace issued a formal denial after Chris Bryant claimed senior figures had sought to relay their concerns directly to No 10.
Mr Bryant told BBC: "Very senior people at Buckingham Palace were very troubled by the appointment of Andy Coulson and tried to make it absolutely clear to the Prime Minister. I am not sure whether this information ever got directly to the Prime Minister, but it certainly got to senior figures at Downing Street."
However, a Palace spokesman said: "On no occasion did any officials from Buckingham Palace raise concerns to Downing Street and indeed it is outrageous to suggest this." A No 10 source described Mr Bryant's claims as "scurrilous" and "complete rubbish".
Meanwhile, a senior Cabinet minister has defended David Cameron's handling of the phone-hacking scandal as the Prime Minister prepared to face a barrage of MPs' questions over his role in the affair.
Culture Secretary Jeremy Hunt denied that the continuing political firestorm represented the biggest crisis of Mr Cameron's premiership so far but he acknowledged that the Prime Minister needs to demonstrate he is capable of the leadership needed to sort out the crisis which has rocked politicians, police and the media.
Mr Cameron flew back to London on Tuesday, having cut short his trade mission to Africa to try to get a grip on the crisis which is now lapping at the gates of Downing Street. He will open a Commons debate on phone hacking for the Government with a statement and will answer MPs' questions, followed by the debate which can run to 7pm
The Conservatives disclosed on Tuesday that former News of the World deputy editor Neil Wallis had given informal advice to Andy Coulson when he was Mr Cameron's communications director in the run-up to the general election.
The role of Mr Wallis - who was arrested last week by police investigating the phone hacking allegations - was already under scrutiny after it was disclosed that he had been working for Scotland Yard as a part-time PR consultant.
Mr Hunt told Sky News: "What people will judge the Prime Minister for is 'does he show the leadership to sort out this crisis?' I think what we have seen in the last couple of weeks is that he is grappling with the problem previous prime ministers have ducked for very many years."