THE water quality at one of Dorset’s favourite tourist spots has dropped dramatically according to the Marine Conservation Society’s Good Beach Guide.

Lulworth Cove, which achieved the highest standard last year, has now dropped two grades to a ‘basic pass’.

Lulworth Estate property manager Nick Kelly said: “The Lulworth Estate prides itself on the quality of the bathing water at all of its beaches and was disappointed that Lulworth Cove has not appeared on the MCS recommended list for 2011, though Durdle Door and Man o’ War beaches are still on the recommended list.

“Regular bathing water testing takes place via the Environment Agency and in 2010 of the 20 occasions the water was tested at Lulworth Cove it never failed the satisfactory standard and on 16 occasions was classified as excellent.”

Mr Kelly said ‘external influences beyond the estate’s control’ can reduce water quality, and this coincided with the 2010 testing, but readings for 2011 have shown that water quality is of the highest level.

Kimmeridge Bay remains on a basic pass, which means only the European mandatory standard for minimum water quality was met.

The only beach in Dorset to have failed was Church Beach at Lyme Regis, where water quality did not meet the most basic of standards set 35 years ago in European law.

MCS said beachgoers may face unprecedented levels of bacteria and viruses in the sea water.

Meanwhile, Weymouth and Portland beaches have been named among the cleanest in the country. Bathing water quality has been rated as ‘excellent’ in the latest edition of the Good Beach Guide, which has been launched by the Marine Conservation Society.

Weymouth central, Lodmoor, and Portland’s Castle Cove and Sandsfoot Castle are among 461 beaches in the UK to achieve ‘recommended’ status in the guide.

It is the third highest number in the guide’s 24-year history. Other top sites along the Dorset coast included Church Ope Cove, Bowleaze Cove, Ringstead Bay, Durdle Door, West Bay, and Hive Beach at Burton Bradstock.

Geoff Petherick, of Weymouth and Portland Borough Council, said: “This is a wonderful tribute to the hard work that goes in to making our beaches clean and safe for residents and visitors.

“Weymouth and Portland Borough Council constantly strives to provide excellent facilities for residents and holiday makers; to maintain the borough’s reputation as a top seaside destination, boost our local economy and improve quality of life for residents.”