Trucker watched Battlestar Galactica on his laptop while driving up the M6

As his 38-ton lorry sped down the motorway, driver Benjamin Trotsman was concentrating intently - on a DVD of the TV series Battlestar Galactica.

He was playing it on his laptop computer, perched on the dashboard of the truck as it roared on through the night.

Other motorists watched in horror as the lorry swerved from lane to lane of the M6 in Cumbria and on and off the hard shoulder.

It also slowed down and speeded up erratically.

Police moved in and Trotsman's crazy drive was halted after 25 miles.

Trotsman, 37, from Bridgnorth in Shropshire, appeared in court last month and pleaded guilty to dangerous driving in the early hours of December 11 last year.

The court heard that Cumbria Police had found the sci-fi DVD in the computer.

This week, Trotsman was back in front of Penrith magistrates, trying to change his plea to not guilty. His lawyer Nigel Beeson claimed that, rather than watching the DVD, his client had been using the computer's roadmap function.

He said: 'My client's case is "Yes, I was driving along, yes, I did have my laptop on the dashboard but it had a Google map or whatever on it".

'In other words, there's a large version of satnav open. Looking at a map would not be dangerous driving.'

But the magistrates rejected the change of plea appeal and referred the case for sentencing next month.

A Cumbria Police spokesman said: 'The driver was seen to be watching a film on a laptop computer that was situated on the dashboard in his cab.

Battlestar Galactica: Trotsman claims he wasn't watching the sci-fi show on his laptop and had a map on the screen

'He appeared oblivious to other motorists.

'This continued from the Kendal area to where the motorway passes Penrith, where police officers observed the lorry, which was still obviously being driven in an inattentive manner.'

Battlestar Galactica, the story of a thousand-year war between mankind and the robotic Cylons, was first made in 1978, when it starred Lorne Greene from Bonanza and the A-Team's Dirk Benedict.

A 're-imagined' version, with lavish modern production effects, began in 2003. It rapidly became a cult hit, not least because many of its plotlines have been seen as allegories of U.S. foreign policy in Iraq.

The show, now in its fourth and final series, has won a U.S. Emmy award for visual effects and Emmy nominations for writing and directing.