PARIS (Reuters) - A British border guard was one of 12 people arrested in France and Britain as part of an operation against arms and drugs smuggling across the English Channel, British police said on Monday. The 36-year-old from Britain s southern port town of Dover and three other British nationals were detained near Calais. French police also seized 34 kilos of cocaine, 7 kilos of heroin and 11 firearms, Britain s National Crime Agency (NCA) said.  The raid took place last Friday and all four remain in police custody. Eight other men were arrested in southern England.  