A woman whose mother was killed in a Valentine's Day road crash says tracing the mystery driver who caused the collision would be 'justice' for her mum.

Emma Herring, 31, described at an inquest in Norwich yesterday how she shouted to her mother, Kim Utting, 52, 'there's nothing I can do' as an oncoming car headed towards them on the A47 at Dereham.

Mother of three Mrs Utting, was travelling from her home in Litcham to Dereham with her daughter for a morning of shopping when a black Pegeot 307 overtook them and continued to drive 'erratically' on the single carriageway.

Andrew Scottow, 25, from Dereham, was driving in the opposite direction towards King's Lynn in a red Skoda when he was forced to swerve away from the black car and ploughed into Mrs Utting's vehicle.

Mrs Herring said she wants the driver caught to stop him driving so dangerously on the county's roads again.

Last night senior police officers appealed for anyone with information about the driver of a black Peugeot 307 to come forward six months after the fatal Valentine's Day crash which killed Kim Utting, 52, and left Andrew Scottow, 25, seriously injured.

Police have trawled hours of CCTV and been unable to identity the driver who failed to stop at the crash on the single-carriageway A47 near Dereham between the Draytonhall Lane and A1075 junctions.

But they have vowed not to close the case until they have found the Peugeot driver, thought to be a white male with cropped hair aged between 20 and 50, and brought him to justice.

Charlie Savage, who is on the serious investigation team and dealt with the case, said tracing the unknown driver was 'frustrating'.

As there was no note taken of the registration number, she said placing the car from the 1,600 black Peugeots in Norfolk was difficult. But she said: 'Until justice is done then the case is still open. We will continue to follow any new leads that come in to the team.

'Someone in Norfolk knows about it. I am convinced of it.'

Mrs Utting's daughter, Emma Herring, who owns the dog parlour K9 Klipz in Litcham, described how the black car was tailgating the green Peugeot 406 in which she and her mother were travelling to Dereham.

She said the pair had decided to take the A47 to the town, rather than the back roads, because the weather had been bad.

'Suddenly', she said, 'there was a black Peugeot behind me – it appeared like he came from nowhere.

'He must have had his foot to the floor to go past me that fast.''

She added: 'It would just be nice to see some justice for mum and have him caught, if nothing else, so the person may think twice about driving so dangerously ever again.'

Mrs Utting, who was a prominent figure on the dog show scene, won a major prize at Crufts in 2008 with her mastiffs. Formerly Kim Dodd, she was the daughter of Donald and June Dodd, of D D Dodd and Son, the fuel supplier company based in Shipdham.

At the inquest yesterday Norfolk coroner William Armstrong told the hearing the driver 'is out there somewhere' and urged him to come forward.

Recording a verdict that Mrs Utting died as a result of a road traffic collision, Mr Armstrong said: 'It's a great shame that the person who was responsible for the terrible calamity has not been brought to justice or been found.

'I would hope even at this stage he might have the good grace to come forward.'

Van driver Glen Harvey, from Norwich, has been a long-distance driver for 30 years and saw the black car overtaking at speed.

'I have never seen anything like it in all my times as a driver', he said.

'The driving was absolutely mad – he was going hell for leather.

'I was expecting police cars coming up behind me, chasing him because of the way he was driving, it was crazy.'

Police also want to hear from the driver of a white lorry, which appeared to have something fluorescent on one of its wing mirrors, and also failed to stop at the crash.

Anyone with information should call police on 101.