Protestors have gathered outside the Mobile World Congress in Barcelona for the second year running to call for a ban on mobile and wireless radio traffic.

A group of around 20 protestors set up outside the main gates as many of the 50,000 delegates streamed out of the show at the end of the day. Placards read 'No Wireless' and mentioned T-Mobile by name.

"We know you make a lot of money from this technology," shouted one protestor. "But the radio waves cause breast cancer. Studies on animals prove it."

The demonstrators harangued delegates via loudhailers and gave interviews to local television crews. Police with a dog handling unit were on hand, but no trouble broke out.

Similar protests took place at last year's conference but with far more protestors. Police at the 2007 event were deployed in a line to keep them from delegates.