LONDON (Reuters) - Britain's most senior civil servant published his private advice to former prime minister Gordon Brown on Thursday to fend off a charge by Brown that he had rejected an inquiry into allegations of phone hacking at Rupert Murdoch's UK newspapers.
The unusual step by Gus O'Donnell, head of the Civil Service and the Cabinet Office, which advises the government, was a measure of the political heat generated by the scandal in Britain, whose current prime minister David Cameron has said politicians of all parties had been under Murdoch's spell.
The seven-page document revealed O'Donnell had advised Brown against holding an inquiry but not blocked any probe.
Brown was accused of breaching protocol by summarizing its findings during an often angry speech on the hacking scandal in parliament on Wednesday.
The March 2010 advice shows O'Donnell told Brown ministers have the power to order a judge-led inquiry on any issue of public concern, although it went on to warn of a number of obstacles that could stand in the way of a probe into hacking.
It said any decision to hold an inquiry could be challenged in the courts. An investigation would be expensive and could set a precedent for the government to hold more inquiries on other subjects.
The timing of the inquiry before a national election, held in May 2010, would "inevitably raise questions over the motivation" of the government, O'Donnell's note added.
However, he also laid out the arguments in favor of an inquiry, saying it might uncover more evidence of wrongdoing within News International and other newspaper groups.
The advice concluded: "From the limited information available, it is doubtful whether this case would merit the holding of a public inquiry."
Cameron has appointed a judge to lead an inquiry into the scandal which has engulfed Murdoch's now defunct News of the World and raised wider questions about media ethics and police corruption.
Several newspapers reported on Monday that O'Donnell had blocked Brown's demand for an inquiry. During his address to parliament, Brown said he had received formal advice "rejecting such an inquiry."
A Cabinet Office spokesman said it is always up to a government minister whether to hold a judicial inquiry.
"Decisions on whether or not to hold a public inquiry, and on its scope and nature, are always the decisions of a minister," the spokesman said in a statement.
Brown, who replaced Tony Blair as prime minister in 2007 and lost the support of Murdoch's newspapers for his Labour Party, has attacked News International repeatedly this week.
He accused Murdoch's journalists of working with criminals to access private details about his family. News International has denied those allegations.
Editing by Philippa Fletcher