Around 24 miles of queues have hit the major road in south-west England this afternoon.
The huge delays have hit the northbound carriageway from J20, near Bristol all the way down to J26 in Taunton, Somerset.
A lorry had stopped in a lane this morning after a tyre burst, forcing one of three lanes to shut.
But despite the lane later reopening, the closure – and usual heavy traffic during the school holidays – have sparked chaos.
Roads and traffic monitoring service Inrix said: “One lane closed, severe delays and queueing traffic for 24 miles due to lorry having a tyre changed on M5 Northbound between J21 A370 (Weston-super-mare) and J20 B3133 Ettlingen Way (Clevedon).
“Congestion to J24 (Bridgwater South). Travel time is 1 hour 15 minutes. Lane one (of three) is closed. Not helped by holiday traffic on the move.”
The delays also come on the predicted busiest day ever for air travel as Brits head to the sun, and Liverpool and Tottenham fans fly to Madrid for the Champions League final.
MORE TO FOLLOW