Dyson Allen has been jailed for life with a minimum term of nine years for killing four siblings in an arson attack in Freckleton.
Allen, 19, had to be helped away by guards as he was taken down to start his sentence.
Sobbing, the killer can barely stand.
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The Prime Minister has praised the former soldier's "huge professionalism" in trying to save the life of Pc Keith Palmer.
The man who carried out the Westminster attack is thought to be British born and was once investigated by MI5, the Prime Minister has said.
Jason Day, who lost his father to stomach cancer at the age of 12, broke down in tears as he explained his shock exit during the WGC event.