Hours upon hours of delays are coming to the M25 this weekend.

That is because the National Grid will be transporting its big load of a transformer.

The equipment, which weighs in at 143 tonnes, will be carried on a special transporter measuring 68 metres long and 5.3 metres wide.

But here is the catch, it will take up two lanes and can only travel at about 12 miles an hour.

Aleksandra Zefirova, National Grid Project Engineer said: “Our network operates smoothly, safely and efficiently over 99.9999 per cent 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.”

The transformer will leave Tilbury Docks via the A109 at about 7pm tonight (Friday) and travel north until it meets the A13.

It will travel along the A13, onto the A1306, and continue until the junction with the A282 towards the Dartford Crossing.

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

The delivery vehicle will arrive at Clacket Lane Services at approximately 4am on Saturday, August 18 and will leave at approximately 6am the following day.

The transformer will then exit the M25 at Junction 11 and continue on the A320 south until the roundabout with the turning for the A245.

It will follow the A245 and B385 on Woodham Lane, before turning right into Pinewood Grove, left into Parkside and into the substation entrance.