It is the ultimate haven for those wanting to play Robinson Crusoe ? A private island with its very own private beach, woodland and a 30ft high cliff has gone on the market with offers of over £1 million considered.

Long Island, which is uninhabited and one of five in the harbour, covers 30 acres at low tide and is surrounded by marshes that are a haven for wildlife. There is no jetty, so visitors gain access to the island using a flat-bottomed boat which is run up the beach.

Stephen Noble, the estate agent who is working on the deal, said: “It is incredible to have a completely unspoiled island in a harbour like this. It has wonderful wildlife [and] would be ideal for someone who wanted to live an outdoor life, or for a wildlife trust or a multi-millionaire.” There are certainly no shortage of multi-millionaires in the area – the island is close to the Sandbanks peninsula, recently ranked as the world’s fourth most expensive place to live.