John Massey is understood to have hid in the prison's gym yesterday until he could sneak on to the roof and escape over the wall without being stopped.
It is thought his makeshift rope was made from bedsheets.
Pentonville was described by prison inspectors as one of Britain's most challenging jails to run last year, but the inspection also found "no obvious problems with physical security".
More top news
Appeal judges are to decide on Thursday whether a woman can use the frozen eggs of her dead daughter to give birth to her grandchild.
The £70 million F-35B jet arrived at RAF Fairford in Gloucestershire, two years after engine trouble postponed its first scheduled visit.
Joseph Thoresen beheaded a man his girlfriend said had sexually assaulted her with a machete and threw his head into the woods, reports say.