Traffic bosses are urging drivers to take a lengthy diversion on the M1 after a "vehicle struck a bridge", causing a "serious collision". The M1 in Hertfordshire is currently closed south-bound between junction 8 at Hemel Hempstead and junction 6 of the M25.

       Emergency services, including Hertfordshire Constabulary and Watford Police are at the scene along with National Highways traffic officers. Live traffic alerts suggest drivers will be stuck in traffic for at least another 90 minutes with queues stretching eight miles - and into rush hour.

       "If this closure impacts on your planned route, please allow extra journey time. Plan ahead, you may wish to re-route or even delay your journey," a National Highways spokesman said.

       Some smaller roads, especially the A1417 is also experiencing congestion due to the closure. It is not yet known when the road will reopen and the extent of any injuries.

       Hertfordshire Police have been contacted for a comment.

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