Stewart Nicholson, 43, and son Connor, six, died after their horse-drawn carriage and the tanker were in collision on the A66 near Coupland Beck, Appleby at 1800 BST on Tuesday.

Mr Nicholson was a member of the travelling community and the pair were from the Peterlee area.

A spokesman for Cumbria Police said the driver, who was not injured in the incident, was arrested on suspicion of dangerous driving and later released on police bail.

The spokesman said the caravan in which the two were travelling was a traditional gypsy-style caravan with a curved roof.

He said: "Around 11,000 gypsies come to this area from all over the country at this time of the year for the Appleby Horse Fair.

"Some hire these traditional caravans for the event."

The dual carriageway was closed in both directions for five hours following the incident.