National Highways has asked drivers to plan their journey in advance and allow extra time as heavy traffic is expected.

The annual show, which is held at the Westpoint Arena, starts tomorrow (Thursday 30 June) and continues over the weekend.

Up to 100,000 people are expected to attend the event in Clyst. St. Mary, near Exeter.

Increased traffic is expected on the M5 north and south of junctions 29 and 30. The A30 east and west of Exeter as well the A38 south of Exeter is also likely to be busy.

Traffic on the M5 will be directed to use junction 30 via the A376 and A3052, while A30 westbound traffic will be directed to exit at the Daisy Mount junction and use the B3180 and A3052.

Thursday morning is expected to be the busiest day.

John Ingram is National Highways' Emergency Planner for the South West. He said: "We are working closely with our partners at Devon County Council and Devon and Cornwall Police to give drivers as much advice as possible to help them plan their journeys during this busy period, and our traffic officers will be patrolling the M5, A38 and A30 to assist with any breakdowns and incidents.

"Junction 30 of the M5 could be particularly busy and the north approach to junction 30 could also see significant increases in traffic between 8am and 10.30am over the three days when visitors to the Devon Show could be using the motorway at the same time as local, freight and holiday traffic.

"The A30 east and west of Exeter and A38 south of Exeter could also see increases in traffic, and drivers are advised to plan their travel routes well in advance, and to keep up to date with the latest road conditions. Yellow signs will advise show visitors which route to take on the approaches to the show."

You can access up-to-date information travel information on local radio and the @HighwaysSWEST Twitter feed, or you can call the National Highways Information Line on 0300 123 5000 or by accessing this website.