Update: One lane closed on M4 following lorry accident

The incident happened after the lorry driver suffered a medical episode.
Police were called to the scene on the westbound carriageway of the M4 between junctions 12 (Theale) and 13 (Chieveley) at about 4.30am.
The lorry had veered off the road and into a ditch.
One lane will remain closed while recovery takes place.

Update:
At 3.20pm, the lorry was recovered and the lane re-opened, however, travel time is still about 40 minutes.