High street rental values in market towns across Norfolk and Suffolk have fallen dramatically over the past decade as out-of-town shopping and the internet have taken their toll.

The cost of prime retail space has decreased in towns such as King's Lynn, Lowestoft and Great Yarmouth, according to a commercial property expert.

The combination of high business rates, parking costs and competition had led to a softening of demand and subsequent decline in rental value, said Adrian Fennell, a partner at Roche Chartered Surveyors.

Great Yarmouth has seen the largest reduction with average rents for prime zone A retail space falling 47% from £75 per sq m to £40.

King's Lynn fell 31% since 2007, from £87.50 per sq m to £60, while Lowestoft has fallen 43% from £75 per sq m to £42.50.

'King's Lynn, Great Yarmouth and Lowestoft all have [negative] growth which is significant. The main reason recently is the exceptionally high [business] rates which have stagnated growth, even with the revaluation,' Mr Fennell said.

'King's Lynn and Great Yarmouth have extremely strong out of town representation with the Hardwick and Gapton Hall retail parks.'

Ipswich and Thetford had seen drops of around 20% while Bury St Edmunds bucked the trend rising 9%, which Mr Fennell said was helped by its proximity to the booming Cambridge market.

Mr Fennell said concessions on business rates would help, as well as cheaper parking to help bring more shoppers into towns.

He said: 'Parking charges are also an issue because if you are doing everyday shopping you don't want to pay £3.50 for two hours.'

Abbie Panks, centre manager for King's Lynn's Vancouver Centre said many towns had seen their rents fall with those in East Anglia no different to most.

Lowestoft Vision chairman Danny Steel said although rents had been falling there retail sector was still holding up.

'Footfall has dropped this year but the average spend has increased to balance that out.

'Organisations such as Lowestoft Vision and the other BIDs are doing lots of work to bring people in,' he said.

Mr Fennell was speakeing at a joint Birketts, BDO and Roche property seminar in Norwich.