By Graeme Murray & Robert Dalling Brits have been advised against swimming in the sea at 25 popular UK beaches by an environmental campaign group. The alert has been issued for seafront destinations and beaches in Wales after pollution caused by storm sewage. Other areas have also received a poor water classification which warns about swimming in the areas. Surfers Against Sewage, a marine conservation and campaigning charity warned about the effluent on beaches on its website and said there had been storm sewage issues within the last 48 hours in a number of areas . The beaches and seafront l…