It had been feared that over-running roadworks on the A47 at Dereham would cause unprecedented traffic jams later this month as tens of thousands of people battled to get to the Royal Norfolk Show.

It had been feared that over-running roadworks on the A47 at Dereham would cause unprecedented traffic jams later this month as tens of thousands of people battled to get to the Royal Norfolk Show.

But now, although roadworks will still be carrying on, to help ease the traffic flow the Highways Agency has decided that on the two show dates, June 27 and 28, it will reopen the westbound slip roads that it needs to close to finish part of a £5m project to strengthen and improve the A47 between Ascot Gardens subway and Etling Green junction.

The Royal Norfolk Show attracts 100,000 people each year and is the largest two-day agricultural event in the country.

John Purling, the chief executive of the Royal Norfolk Agricultural Association, which runs the event, had initially branded the overrunning of the roadworks a “disaster” but has now welcomed news that the slip roads will be reopened.

The roadworks began in April and are now running behind schedule because of the bad weather during the last bank holiday weekend and because of problems installing new concrete drainage channels works.

The main part of the work was due to be completed just before the Royal Norfolk Show but it will now be completed by July.

Throughout the works a 50mph speed limit has been in place. The eastbound carriageway and slip roads have been shut since the beginning of May and a contraflow system on the westbound carriageway has been in place since then with signed diversions.

On Monday, the eastbound carriageway and slip roads will reopen and work will begin on the westbound carriageway which will then close along with the westbound slip roads. There will then be a contraflow system on the eastbound carriageway for about three weeks.

The Highways Agency urged drivers to allow extra time for their journeys to the show.

The diversion route while the slip roads are closed comes off the A47 at North Tuddenham, runs down to the B1147, down Norwich Road into Dereham, along Matsell Way, down Neatherd Road, along Wellington Road, down Swaffham Road, along the B1146 and along Dereham Road through Scarning before rejoining the A47 just past Wendling. It will be fully signposted.

For more details visit the Highways Agency website at www.highways.gov.uk or call 0845 7504030.