Europe's longest chalk reef, which lies off the North Norfolk coast, could be included in a ground-breaking scheme to protect the underwater gems around England's shoreline.

But while the reef that runs offshore from Sheringham to Mundesley has been earmarked as a marine conservation zone (MCZ), there is some disappointment that it has not got the nod for even greater protection.

Meanwhile, seven special spots on the county's coast have been included at the higher level, in a list of possible 'reference areas' in the proposals to ministers.

The areas have been identified for supporting special animal, bird or plant species - and will be held up as examples of what can happen when there is no human interference in an environment.

More than 100 MCZs have been proposed as a response to the 2009 UK marine bill, which seeks to give formal protection to more than 25pc of the nation's coastal waters - up from the current 1pc.

They will be assessed by an expert panel, which will decide levels of protection before the government makes its final decision, probably next year.

The locations likely to be reference areas are:

? An area five miles off Trimingham, where there is a high density of blue mussels

? Two saline lagoons - Seahorse Lagoon and Arnold's Marsh - at Cley Marshes nature reserve, which were recommended for their starlet sea anemones

? Another area at Cley Marshes, which is seen as special for its saltwater reedbeds

? A spot at Morston salt-marsh, to protect the coastal salt-marsh and saline reedbeds

? An area of Stanley's Cockle Bight at Blakeney Point, chosen for its seagrass bed

? The peat and clay beds near Holme-next-the-Sea, in the area where Seahenge was found

? The Wash Approach, 27km off the Lincolnshire coast, where the seabed supports a 'diverse' range of flora and fauna.

The proposal to earmark the Sheringham reef as an MCZ came after in-depth talks with interested groups, including dredging firms, fishermen, divers and windfarm companies.

Rob Spray from the Marine Conservation Society, whose underwater photography helped to reveal the extent of the Sheringham reef and the wildlife it supports, had misgivings.

He said: 'The lack of the reference area for the chalk reef is the biggest oversight. It would be a chance to monitor the health and confirm the importance of the chalk - so recently brought to public attention.'

He said making it an MCZ would be no more than the 'status quo', and meant there was 'no chance of seeing how it would thrive if completely left alone'.

He admitted that it meant it 'would not be allowed to get any worse', and added that 'intractable objections' from opponents had 'blocked' the idea of bolstering protection.

The ultimate aim of the bill is to safeguard important natural habitats while allowing others activities such as angling, commercial fishing, surfing and marine dredging to go ahead.

Dr Peter Richardson, biodiversity programme manager at the Marine Conservation Society, said: 'We think we need these protected areas to allow areas of the seabed to recover.

'Aggregate dredgers and fishermen have pretty much had free rein for centuries. The studies show a general degradation of seabeds and marine species.

'In order for our eco-systems to recover, we think there should be some areas protected. That will then lead to functioning ecosystems and sustainable fisheries.'