Dualling the A47 would make accidents less likely to close the whole road, according to Norfolk Police.

Chris Hinitt, serious collision investigation team and road safety inspector with the Norfolk and Suffolk Roads and Armed Policing Team, said it is always a challenge to work on a single carriageway following a crash.

He said: 'When you first arrive on your first priority is to save lives and do life preserving. In some accidents we can close one lane and keep the other lane open.

'It is always a challenge if we have to work on a single carriageway road where there has been a collision. A big long section of the A12 and A47 are single carriageway and quite often an accident will block the whole road.'

He added: 'The straight parts of the A47 and A12 encourage people to go on the speed limit or over the limit and if you have a collision the chances are they are likely to be more impactful and close the road.

'If you have got a two lane carriageway like the A11 and A12 then you would get they option of partially closing the road rather than fully closing it because we have more to work with.'

The cost of a fatal accident on Britain's road is estimated to cost more than £2m according to the most recent statistics from the Department for Transport, with the prevention of a serious collision worth nearly £250,000 per accident.

For the police, their first priority after saving lives remains safety, regardless of the impact closing a road might have on other road users.

Insp. Hinitt said: 'You can have a dual carriageway road that has only two lanes with a barrier down the middle and we don't get a lot of that on the A47.

'If we have to work on a collision the problem is that you have other cars coming the other way and is that safe for the staff?'

He added: 'We are acutely aware that they are really important for business and the community and the knock on effect of closing that road will have knock on effects for places nearby as well.

'It is always in the forefront of our minds to open the road as quickly as possible but what we won't do is sacrifice the evidence because I don't want to go to a family and say I needed to open the road so someone could get home and I couldn't get the evidence.'