Walsh riled over Lashes' fateX Factor judge Louis Walsh was left fuming after two of his acts came bottom of the public vote on the first live show of the 2009 series.
Bad Lashes were ousted after a sing-off against Girlband. Simon Cowell declared both groups "shocking", but Walsh snapped back that Cowell had never had a successful girl band of his own.
Presenter Dermot O'Leary ticked off both judges for "petty squabbling".
Longstanding rivals Cowell and Walsh had traded insults throughout the show.
Cowell claimed listening to Bad Lashes was "like eating water". And he ordered Walsh to apologise to Alexandra, who is making a comeback on the show after being rejected in 2005.
But Walsh mocked Cowell mercilessly for having a crush on Spanish contestant Ruth, and forced him to grovel to Scott for choosing such a poor song.
Teletext