Overview
- The westbound carriageway closed in Wiltshire around 3am Sunday after a collision between a BMW and a National Express coach between Junctions 14 and 15.
- Wiltshire Police say the BMW driver, a man in his 20s, is in hospital with life-threatening injuries, with no other injuries reported.
- National Highways says the road is likely to stay shut for some time due to a large oil spillage and ongoing collision investigation.
- Drivers are being sent on a hollow-square diversion via the A338, A4, B4192 and A419, and traffic is heavy through Marlborough and nearby towns.
- A separate westbound crash closed Junctions 16 to 17 Sunday evening, increasing pressure on routes across the region.