A campaigner who started a petition to have 'cheese wire' restraints removed from the A11's central reservation has called for evidence that they are safe for motorcyclists after the Highways agency defended their use.

Simon Frampton says the controversial wire restraints, which are being used on the newly dualled stretch of A11 between Thetford and Barton Mills, are a danger to motorcyclists and banned in a number of European countries.

But in a letter to Mr Frampton, the Highways Agency said it had tested the restraints on 1500kg family car and smaller vehicles such as a VW Lupo.

He said: 'They say they have tested the barriers on cars but there's no evidence they have been tested on motorcycles and it's a different thing altogether.

'We go under the wire or hit the uprights, the bike gets caught in the upright or cables and it can catapult you over. It either does that or cuts bits off of you, that's why we call them 'cheese wire',' he said.

Mr Frampton said bikers only need to hit the barriers at 30mph for serious damage to be likely and said a number of European nations had banned the design.

He also claims the Highways Agency admitted it had reservations about the restraints in 2005.

Mr Frampton, a senior project manager in a construction firm, said the wire barriers cost more to produce than a concrete alternative, and questioned the reasons for their use.

'You do wonder why they would be using these when they are more dangerous and more expensive.

'In my line of work you often see people signing long-term contracts for the supply of this kind of thing and I wonder if this is what has happened here and they can't get out of it,' he said.

A spokesman for the Highways Agency insisted the restraints were safe for use.

'Central reservation safety barriers are put in place to increase road user safety by preventing vehicles crossing over to the opposite carriageway and reducing the risk of more serious injuries.

'All barrier systems are tested by an independent authority to ensure they exceed our stringent design standards.

'The barriers in this instance were procured via the usual tender process to ensure best value for money for the public whilst ensuring high standards of road user safety are met,' he said.

What do you think of the use of the steel wire safety restraints? Let us know by emailing reporter Andrew Fitchett on andrew.fitchett@archant.co.uk