Billionaire investment guru George Soros has said that it is "impossible" for Britain to reject adoption of the euro. Mr Soros, whose currency investments have earned him a formidable reputation, warned that there were still concerns over Europe's single currency. Harmonisation of taxes among EU states was needed to support a euro which was still "a work in progress", Mr Soros told GMTV's The Sunday Programme. But he added that it would be "very difficult and very detrimental for Britain to be seen to be staying out".