By Daniel Hunter
The Organisation for Economic Co-operation and Development (OECD) has attacked the "extremely aggressive" tax plans utilised by technology firms.
Pascal Saint-Amans, head of the OECD's Centre for Tax Policy, is charged with reforming global tax rules. He says new rules would force companies to pay more tax in countries where they sell goods or generate revenues.
Mr Saint-Amans said businesses should not use tax havens, or divert profits away countries where they are generated. He said that new global rules would be implemented "well before" 2020. It would mean the likes of Google, Amazon, Apple, Microsoft and Facebook paying more tax to the UK Treasury, he said.
The UK government has its own plans to crackdown on corporate tax avoidance, but Mr Saint-Amans said any rules would have to be "co-ordinated" with the OECD's.
The government estimates that US tech giants like Google would be forced to pay hundreds of millions of dollars to the Treasury.
"Most of these companies have been extremely aggressive, pushing the boundaries of what is legal," Mr Saint-Amans
"They have tried schemes that cannot resist further examination by tax administrations.
"My advice would be instead of focusing on tax planning, please do the wonderful job you are doing on innovation and be much more conservative on tax planning.
"They have been extremely aggressive and that may have sounded unfair to the audience - that you have giants making billions in profits and not paying taxes where they operate."