A section of motorway is expected to be closed for several hours following a multi-vehicle pile-up this afternoon. 

The M1 has been closed in both directions between J14 (Milton Keynes central) and J15 (Northampton) after a lorry crossed the carriageway and smashed into several other vehicles. 

Earlier on, an air ambulance landed on the carriageway to transport a casualty to hospital. 

The road is not expected to return to normal conditions until approximately 2am.