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
The female runner almost collapsed towards the end of a half-marathon - but still completed the race with a helping hand or two.
South African anti-apartheid leader Ahmed Kathrada has died at the age of 87.
Cyclone Debbie has made landfall in Australia, battering the Queensland coastline with winds of up to 163mph (263km/h) and heavy rains.