Police are warning motorists to expect delays on the M4 on Saturday when a giant transforner from Didcot power station is moved.

A specialised load transporter, one of the largest loads moved acros the county, will be escorted by Wiltshire officers from Junctions 14 to 18 on the M4.

The transporter and its load will measure 4.87 metres (16ft) wide, 4.98 m (16ft-04ins) high with an overall length of 89.67 m (294 ft) and gross weight of 637.80 tonnes.

A polioce spokesman said: "Due to the size of this transporter it will be extremely slow moving and will have the potential to create congestion.

"Wherever possible disruption will be kept to a minimum but hauliers and motorists are asked to be patient if they come across this load. Anyone travelling over this period to catch a flight or meet appointments should allow sufficient additional time.

"Regular updates and travel information in respect of this abnormal load will be passed from our control room at Devizes when appropriate to help motorists plan their journey."

The move will begin at around 5pm from M4 junction 14 where the load will be transported in convoy, along the M4 to junction 18, then on to the A46 where it will stay in a lay-by until Sunday morning awaiting collected by Police Officers from the Avon & Somerset Constabulary for onwards travel to Avonmouth Docks.

The transformer will be taken to Avonmouth Docks and on to Siemens in Germany.

The escort will be provided by off-duty officers who are being paid by the contractor.