‘HOLD the line at Hengistbury Head – or increase the risk of a flooding disaster’.

These men are fighting a proposed change in the coastal protection plan.

They say in time it could lead to the flooding of Christchurch Harbour, and the erosion of Hengistbury Head.

For the last five years, the council’s policy for the beach at the head has been ‘Hold the Line’ – a commitment to keeping or upgrading the sea defences.

The proposed policy for the next five years is ‘Managed Realignment’ – but the Hengistbury residents association fears that could mean defences are left fatally weak.

They are anxiously waiting to see if the Environment Agency approves the change, when the final Shoreline Management Plan is revealed in April.

The group want extra groynes put in between Double Dykes and Long Groyne to reduce erosion and reduce the chances of a sudden breach during a storm.

A consultants' report says a breach could happen at any time with a bad enough storm – and the group said it would have “disastrous consequences” for people living nearby, and potentially for the whole future of Poole Bay.

Tony Bayliss, 67, building surveyor, said: “The neck of land at Double Dykes is already very narrow and we think that it should be protected from becoming even more flimsy.

“If there is a breach and it is not possible to stop up the new tidal stream, the Long Groyne at Hengistbury Head will be unable to do its job.

“Without the Long Gryone acting as a headland for Poole Bay, there will be huge erosion forces along the sea wall and promenades.”

Cllr Robert Lawton, cabinet member for Environment, said: “For the majority of Bournemouth's coastline, including all the built-up area and Hengistbury Head, the policy is to ‘Hold the line’. “We are proposing to do all we can to ensure that we protect our coastline for future generations and the Shoreline Management Plan is crucial to achieving this.”