The Marine Conservation Society (MCS) said the amount of plastic found on the coastline had increased by 126% since its first annual Beachwatch survey in 1994.

Carrier bags, drinks bottles and even plastic-based cigarette butts contributed to the "tide" of plastic waste which made up more than half (58%) of the litter blighting our beaches, the MCS Beachwatch 2007 study found.

The conservation organisation said the plastics could remain in the marine environment for hundreds of years and prove fatal for wildlife including seabirds, turtles and whales.

More than 170 marine species have been recorded mistaking litter for food, and as a result starving, being poisoned or suffering fatal stomach blockages.

Emma Snowden, MCS litter projects co-ordinator, said: "The results are truly shocking. In the last 10 years, plastic bottles have increased by 67%, plastic bags by 54% and cigarette butts by 44%.

The 2007 report saw almost 4,000 volunteers surveying 168.5km of coast in September 2007 and removing more than 346,000 items of litter ranging from cloth and fishing line to glass and lolly wrappers.

The MCS said the litter was recycled where possible or disposed of with the help of local authorities.

The number of items of litter per kilometre rose slightly on average across the UK from 2006 to 2007, increasing from a density of 1,988 items per kilometre to 2,053 - an average of two pieces per metre.

The survey found the largest single source of beach litter was from visitors and recreation on the coast (35.3%), followed by fishing litter (13.7%), sewage-related/sanitary waste (6.1%) and shipping litter (1.8%).