An official inquiry will hear evidence today from the widow of a British weapons expert who killed himself after being dragged into a vicious row with Tony Blair's government over the case for war in Iraq.

The widow of David Kelly, who committed suicide in July after being named as the source for a BBC report accusing the government of exaggerating the Iraqi threat, will give a poignant insight into her husband's state of mind hours before he died.

Kelly's death plunged Blair into the worst crisis of his six-year premiership and triggered a potentially explosive inquiry which has delved into details about how his government made its case for war in Iraq and how it treated Kelly.

The quietly spoken scientist was grilled by a parliamentary committee on July 15 over his unauthorised meeting with a BBC journalist. Two days after the occasionally hostile questioning, he slashed his wrist in woods near his home.

An inquiry spokesman said Janice Kelly, 58, and her daughter Rachel were expected to go in person to the central London Royal Courts of Justice, where the inquiry is being held, but may give evidence via video link from a separate room.

The inquiry, which has already quizzed Blair, also hears from Kelly's sister, his daughter and her fiance, followed by friends, a psychiatrist and a religious leader later this week.

Media reports yesterday said Kelly's widow would tell of the intense pressure her husband felt after he admitted briefing a BBC reporter who had accused the government of "sexing up" a dossier on Iraq's weapons.

The Sunday Telegraph said Janice Kelly had told friends she and her husband had a series of rows in the hours before he died.

The Observer newspaper said on Sunday that Kelly - widely acknowledged as Britain's leading expert on banned Iraqi weapons - wrote an article before his death saying military action was the only way to "conclusively disarm" Iraq.