Traffic is being diverted by way of the exit and entry slip roads.
https://www.express.co.uk/news/uk/2040824/m1-traffic-live-severe-delays-road-closure
M1 site visitors LIVE: Nightmare on key motorway as drivers face ‘2-hour delay’ | EUROtoday

Traffic is being diverted by way of the exit and entry slip roads.
https://www.express.co.uk/news/uk/2040824/m1-traffic-live-severe-delays-road-closure