A police officer has been knocked unconscious by protesters as the first trouble broke out at the student tuition fees march, with demonstrators breaching barriers into Parliament Square. The officer was dragged to safety by colleagues after being hit on the head in Kingsway as tens of thousands of students gathered in London in a last-ditch protest against the Government's plans to allow English universities to charge up to £9,000 per year in fees from 2012.

Credit : RUDY CECH / BARCROFT MEDIA