Stockshots of Eurostar passengers and trains as Britain shakes up its travel rules for European nationals heading to the UK. They will now need an Electronic Travel Authorisation (ETA) to do so, a move which the British government says will strengthen border security. It is similar to the ESTA system in operation in the United States and is mandatory for all European visitors to Britain from April 2, following its roll-out for US, Canadian and other visa-exempt nationals in January. STOCKSHOTS of Eurostar trains and passengers