Police are appealing for information to trace whoever threw a supermarket shopping trolley from a bridge near Pucklechurch onto the M4 early this morning.
At least two vehicles hit it and were damaged at around 1.15am on the eastbound section between junctions 18 and 19, near the Pucklechurch Road overbridge on the B4465.
Traffic officer PC Mark Lambert said: “This constitutes a serious risk to life and anyone who has information or has seen anything that may be linked is urged to contact police.”
If you can help, call 101.
