A giant transformer will be travelling over the Dartford Crossing this evening - potentially causing delays for motorists.

The mammoth 143-tonne structure is set to make its way over the Queen Elizabeth II Bridge at 10pm.

The bridge will be closed for about 20 minutes while it makes the crossing into Kent.

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Due to weight restrictions, police will implement a rolling road block as the device crosses the river at a speed of just 12mph.

It is being transported from Essex to Surrey using a special lorry and will be used to deliver electricity to the South of England.

The transformer will leave Tilbury docks at about 7pm via the A109, and will travel north until it meets the A13.

It will then be driven onto the A1306, and continue until the junction with the A282 towards the crossing.

Once it has crossed the bridge, it will exit at Junction 1A and re-join the M25 at Junction 2 due to a weight restriction between these junctions.

To reduce traffic disruptions the vehicle will arrive at Clacket Lane Services at approximately 4am on tomorrow, and leave at 6am the following day.

It is set to arrive at the substation in Surrey by 4pm on Sunday.

National Grid project engineer Aleksandra Zefirova said: “Our network operates smoothly, safely and efficiently over 99.9% of the time, a statistic we’re very proud of.

“Millions of people rely on us to supply their electricity without interruption, day in, day out and so it’s important that we keep our substations and the equipment in them working efficiently.”

If anyone has any questions about the delivery, they can call the National Grid hotline on 0800 0193235 between 9am and 5.30pm or email info@communityrelations.co.uk