PETER COSTELLO says John Howard appears incapable of taking responsibility for losing government and his seat, in his toughest public attack on his former leader.

The former prime minister has opened a new war by criticising his former deputy in his memoir. Mr Costello told the Herald: "It's a self-serving account … he appears to be incapable of taking responsibility for the defeat of the government and for losing his seat of Bennelong.

"There's no point in trying to blame other people. He was the leader. He was responsible."

By claiming that Mr Costello mishandled a planned leadership transition and branding him "elitist'', Mr Howard has revived and escalated their long-running rivalry.

This could damage the legacy of the Howard years and interfere with the efforts of the Liberal leader, Tony Abbott, to keep scrutiny on the Labor government.