RUBBISH on Scotland's beaches increased by 20% in a year showing anti-litter campaigns are now falling on deaf ears, according to a leading marine charity.

The Marine Conservation Society (MCS) says the growing problem shows the pressing need for the long-delayed Scottish marine litter strategy being developed by the Scottish Government.

Plastic debris made up almost 56% of all the litter found on Scotland's beaches during a single weekend last September, according to the annual Beachwatch Big Weekend Report published today by MCS.

However, the amount of plastic overall on UK beaches in 2012 rose by just 3% compared with the previous year.

Scotland had the third-highest litter levels (2041 items/kilometre), representing an increase of 20% compared to figures relating to Beachwatch Big Weekend 2011. The highest was Northern Ireland with 8224 items/km, representing an increase of more than 60% compared to the previous year.

MCS said the amount of rubbish, such as wrappers and bottles, highlights the need for a proper litter policy and indicates various anti-litter campaigns now need to be re-invigorated for a new generation.

Anne Saunders, MCS Scottish projects officer, said the continued rise in beach litter is worrying, but the fact that much of it is plastic and unlikely to break down is even more concerning. She said: "As we continue to embrace the concept of a throwaway society, it's no surprise plastic dominates the litter we find. Last year we saw an encouraging drop in the amount of sewage- related debris on Scottish beaches – that's the stuff people shouldn't put down their loos but do, like sanitary towels, nappies and condoms – but this year's figures show that has risen again which is very disappointing.

"2014 is a busy year for Scotland with the Commonwealth Games and the Ryder Cup taking place here. Consultations on both a national litter strategy and a marine litter strategy must take place this summer and will show Scotland leading the way through having wide-ranging mechanisms to combat littering on land and at sea by the following year."

In Scotland, almost 500 volunteers cleaned 35 beaches, covering more than 10km. They collected 20,951 items, filling more than 254 bags. For every kilometre surveyed, 2041 pieces of litter were found, compared with 1696 during the previous survey.

The latest figures also reveal a rise in the number of sweet and lolly wrappers on Scottish beaches as well as more than 110 plastic drinks bottles for every kilometre surveyed.

The MCS figures depend on the number of volunteers in any given area and the number of beaches they chose to clean.

In the Edinburgh area, 97 volunteers cleaned up two beaches, Cramond and Hopetoun House, filling 18 bags, or 16,900 items, of rubbish per km, the largest total.

Across the Highlands, 11 volunteers looked at two beaches – Caol, near Fort William, and the north shore of Munlochy Bay in the Black Isle, filling seven bags, or 2715 items, per km. In Orkney, 15 volunteers looked at one beach and filled just one-and-a-half bags from a 100-metre stretch of Dingieshowe.

A Scottish Government spokesman said: "We all have a responsibility to ensure our rubbish is disposed of in the proper manner. The Scottish Government will consult on a draft Marine Litter Strategy from this summer which will aim to address the levels of litter present in the coastal and marine environment, and contribute to international action through the EU Marine Strategy Framework Directive."