Experts to hunt the missing minutes on Nixon tape

It is one of the enduring mysteries of the Watergate scandal, a crucial 18.5-minute segment from the White House tapes erased under murky circumstances, in which Richard Nixon and his chief of staff, HR Haldeman, discussed the notorious 1972 break-in at Democratic Party national head- quarters that was to cost them their careers.

Now, thanks to digital technology, those minutes may be recovered, at least in part. This week, the National Archives in Washington said it was authorising sound-recording specialists to examine the tapes to see if they can reconstruct the conversation, based on traces left behind after the erase button was pushed.

"Can it be done? Absolutely, it's possible," a member of the National Archives advisory committee, Steve St Croix, told the Los Angeles Times. In the early Seventies, tape erasure techniques were not as thorough as they became, he said. and that gave him particular grounds for hope.

The specialists will try to map the magnetised particles of iron oxide left on the tape to see if they see make up a decipherable pattern. Historians believe the missing segment may contain evidence that President Nixon wanted to use the CIA to thwart the investigation into the burglary, at the Watergate building in Washington three days earlier.

Other evidence of abuse of power eventually surfaced in another White House recording – the so-called "smoking gun" tape – that led to Mr Nixon's resignation in August 1974.

The conversation with Mr Haldeman, who, like Mr Nixon, is now dead, was erased by the president's secretary, Rose Mary Woods. She said it happened accidentally while she was answering the phone.