Part of the stricken M1 has reopened after being closed for more than 36 hours, easing congestion for sports fans and Easter holidaymakers.
The motorway has been closed since shortly after 4am on Friday but the Highways Agency said it had opened one northbound lane.
A spokesman said the southbound carriageway would remain shut between junctions one and four "until it is safe to be reopened".
The motorway closure led to delays on the A1, A40 and A406 as motorists took alternative routes, said AA Roadwatch.
Engineers continued to assess the damage caused by a fire in a scrapyard beneath the M1 between the M25 and North Circular Road in north London.
Around 40 firefighters tackled the blaze, which broke out at a scrapyard site close to Scratchwood Services and Ellesmere Avenue in Mill Hill.
A number of gas cylinders were involved and a hazard zone was set up in case they exploded in the heat, London Fire Brigade said.
About 50 people living in properties near the scrapyard were temporarily evacuated as a precaution while the cylinders, some of which were acetylene, were cooled and made safe. Train lines close to the scene were also shut down.
Highways Agency engineers were given access to the site of the fire underneath the motorway to assess the extent of the damage.
The closure forced a change of route for many leaving London for an Easter holiday, football fans heading to Wembley and those travelling to the capital for Sunday's London Marathon.