The newspaper quoted Johnson as saying he was only bound “in theory” by the new legislation.
“We’re in quite extraordinary territory when the prime minister says he is above the law,” Corbyn told Sky News.
Dominic Grieve, a former attorney general and one of 21 Conservative lawmakers ousted from the party this week, said Johnson was unfit for office.
“This is ridiculous, it’s shaming, it’s like a four-year old having a tantrum,” he told Sky News.
A former UK director of public prosecutions (DPP) said Johnson could face prison if he refuses to delay Brexit in the face of court action.
“In conventional cases...individuals who are in contempt of court and fail to purge their contempt are liable to be committed to prison,” Ken MacDonald, who served as DPP from 2003 to 2008 and now sits in the Lords, told Sky News.