Labour life peer Lord Ahmed has been jailed for 12 weeks for dangerous driving by a judge who heard he sent and received a series of text messages from his car on a motorway.

Sheffield Crown Court was told Lord Ahmed was involved in an accident which left a man dead on the M1 near Rotherham, South Yorkshire, on Christmas Day 2007.

But the judge made it clear the text messaging had finished before the accident took place and was not connected to the fatal incident.

The judge, Mr Justice Wilkie, heard Lord Ahmed got on to the M1 motorway at Dewsbury in the early evening of Christmas Day 2007.

The peer sent and received a series of five text messages, all of which were described as substantial, rather than a few words.

The judge said the exchange of messages with a journalist amounted to a conversation, which took place as the peer was travelling at around 60mph over a 17.8-mile stretch of the southbound carriageway.

The judge was told the fatal accident happened close to junction 35 of the motorway.

Lord Ahmed's Jaguar ran into an Audi. Its driver, Martyn Gombar, 28, had crashed minutes earlier and is thought to have been trying to retrieve his mobile phone from the vehicle.

The court was told that subsequent tests showed father-of-two Mr Gombar had been drinking and crashed his car into the central reservation, spinning it round.

As Lord Ahmed approached the Audi, it was facing the wrong way, straddling the two outermost lanes in total darkness.

The court heard another car clipped its wing mirror and a further vehicle had taken such drastic avoiding action that it also collided with the central reservation.

But the judge said Lord Ahmed's text message conversation ended 1.86 miles, (3km) or two minutes, before the collision with the Audi.

He was jailed for 12 weeks for dangerous driving.