David Cameron today calls on the leaders of the world's richest nations to take bold steps to crack down on aggressive tax avoidance. The Prime Minister's move follows allegations that some of the world's largest companies, including Amazon and Starbucks, do not pay enough tax. Following widespread public outrage the coffee giant announced at the end of last year it would increase the amount it paid in the UK. But other companies, accused of underpaying to the tune of millions of pounds, have yet to follow their lead…[David Cameron] told the leaders they had a common interest to ensure a crackdown on aggressive tax avoidance. But he warned they had to work together…He also urged the group to look at toughening the international standards that currently allow companies to decide where to declare their profits to reduce their tax bill.