The culture secretary's prospects for survival in government look dicey as she struggles to shake off sleaze allegations.

The row over the financial dealings of Tessa Jowell and her husband continued to generate damaging headlines in Wednesday's newspapers.

The Home Office's dealings in the case was also called into question, though officials denied any wrongdoing.

And in the Commons, Tony Blair pledged a full investigation.

"We will, of course, examine any allegations that are made and reply to them fully," said the prime minister.

Doubts about Jowell's future deepened on Tuesday, when Number 10 confirmed that cabinet secretary Sir Gus O'Donnell is continuing to investigate her conduct.

The prime minister's spokesman said Sir Gus, Britain's most senior civil servant, was "establishing the facts".

Jowell's position has faced intense scrutiny since weekend reports linked her to an alleged "bribe" paid to her husband, an international lawyer.

Both Jowell and husband David Mills have denied any wrongdoing, but cabinet colleagues are said to doubt whether she can survive.

Sir Gus's inquiry is thought to be focusing on whether investments made by Mills could have created a conflict of interest, and whether any such conflicts were reported to civil servants as required by the ministerial code of conduct.

The Guardian said that Jowell failed to declare her joint mortgage used to raise funds to invest in a hedge fund in the Commons register of interests, although it is not entirely clear that the rules required her to do so.

However the paper noted that as a co-signatory on the mortgage, half of the investment could have been regarded as Jowell's.