The estate of the disgraced ex-president is seeking up to $250m for a massive body of records including some of the most famous evidence of the Watergate scandal.

When "Tricky Dicky" quit the White House in 1974 he left behind 42 million pages of documents, plus 3,700 hours of secretly recorded tapes and thousands of photographs.

All presidents have considered their papers to be their personal property after they left office. Since Herbert Hoover, all but Mr Nixon donated them to government-run presidential libraries.

Archives seized

But when Mr Nixon resigned to avoid impeachment over Watergate, congress passed a law seizing the materials he left behind and putting them in the custody of the National Archives and Records Administration.

There, anyone can read and handle documents bearing Mr Nixon's own handwritten - and sometimes undiplomatic - comments. But no one has heard most of the tapes, which, under court order resulting from additional Nixon-generated litigation, are being cut to remove personal comments.

Nixon left the White House in disgrace

In 1980 the former president unsuccessfully sued for compensation for the loss of his archives.

But he later won his case in an appeals court, which ruled he was entitled to collect for the value of the materials plus interest.

However, Mr Nixon died in 1994 before the case could be finally settled.

Compensation hearing

At the new hearing before a district court in Washington the two sides are set to argue over the size of compensation.

The government is expected to argue that Mr Nixon's heirs are entitled to nothing - and that the collection is worth far less than has been claimed.

The records might raise a fortune on the open market

However, in a pre-trial deposition, a valuer hired by the estate, John R. Payne, said a letter, report, speech draft or news summary bearing "Nixon's minimal comments" such as "good," "excellent" or "bravo" would be worth $100 a page.

Major documents would be worth more he testified.

One photo expert has put a $12m value on the "commercial exploitation" of the secretly recorded White House tapes.

He cited the commercial success of the "All the President's Men" book and movie about Watergate as evidence.

The government argues that commercial values are not relevant since Mr Nixon originally intended to put his collection in a presidential library rather than make money from it.