UPDATE: The Second World War bomb has exploded.

Norfolk Police has confirmed the detonation was not planned.

READ MORE: Live updates as bomb explodes in Great Yarmouth

A major incident has been declared following the discovery of an unexploded bomb in Great Yarmouth.

Army specialists are currently making preparations to detonate the device, but this has been delayed due to the proximity of gas main pipes. 

READ MORE: Live updates as cordon remains in place

Here is everything we know so far about the incident.

Eastern Daily Press: The unexploded bomb discovered in Great YarmouthThe unexploded bomb discovered in Great Yarmouth (Image: Contributed)

When and where was the bomb discovered?

The unexploded bomb was discovered by workers at the construction site of the third river crossing in Southtown Road at 11.36am on Tuesday, February 7. 

The device was found during dredging work in the River Yare at Bollard Quay, close to the junction with Boundary Road.

What is it?

It is thought to be an unexploded bomb from the Second World War. 

The bomb is estimated to be around 250kg in weight and the size of an adult's torso.

Why have people been evacuated?

Army specialists believe the bomb is too dangerous to move and a sand wall has been built around it in order to protect the area from the impact of the explosion when it is detonated.

A 400m cordon is in place in the area and hundreds of people have been evacuated from homes and businesses as a precaution.

A rest centre was set up on Tuesday night in order to provide refuge to the evacuated locals.

People who are asked to evacuate are strongly advised to do so and those who are unable to seek refuge with friends and family can go to one of the two rest centres.

During the time of detonation, there will be a 200m compulsory evacuation and a 400m strongly advised evacuation.

The public is asked to stay away from the area to let the specialists work.

A no-fly zone has also been put in place in the immediate vicinity of the device.

Eastern Daily Press: A number of road closures are in placeA number of road closures are in place (Image: Newsquest)

Which roads are closed?

Southtown Road is closed from its junction with Tollgate Road all the way to Beccles Road.

Williams Adam Way and Tollgate Road off Southtown Road are fully closed and Litchfield Road and Boundary Road are partially closed.

On the other side of the river, a police cordon on Southgates Road is still in place with the road shut from Newcastle Road to Main Cross Road.

Pedestrians heading to Gorleston are being advised to walk to the footbridge A47 overpass on Boundary Road. This leads them to Harfrey’s industrial estate and they can walk to Gorleston from there.

Officers are asking pedestrians and drivers to avoid the area.

When will the bomb be exploded?

The head of Great Yarmouth Police, Nathan Clark, has said that works have been put on hold. 

The army has had to stop defusing the unexploded bomb due to the proximity of gas main pipes. 

Specialists are currently working on finding a new approach to the situation and are assessing the risk to local infrastructure. 

Who do I speak to if I have been evacuated and have concerns?

An emergency helpline has been set up for people who require assistance with evacuation from the exclusion zone. This helpline is 01493 330369 and should not be used for general advice.