Ever since the idea of an EU financial transactions tax was mooted, Britain has been trying to push the door to such a tax shut. France meanwhile has been wedging its foot in the door to keep it open. The UK view is that it would be madness for Europe to adopt the tax on its own. But as French president Nicolas Sarkozy campaigns for re-election in April, he has promised to introduce the tax in France prompting London's mayor Boris Johnson to invite French banks to think about relocating to London. If France goes ahead with the tax, it could indeed be London's gain. But another effect would be to increase pressure on the EU to introduce the tax Europe wide, and hence widen the gulf further between Britain and the other member states who continue to bind themselves ever tighter together. The whole episode serves to remind us how important it is to aim for diversity in our investments so that we don't end up heavily exposed to trouble spots. Our fund tip this week offers some instant diversification: it's a global best ideas fund, with low volatility and experienced managers. Meanwhile, as former RBS boss Fred Goodwin is stripped of his knighthood, we assess the bank's bonds - should you boot them out or hold on? In the retailing sector, Dixons has lost the man who was meant to save it. John Hughman reports on the impact on the company. Finally, Mark Robinson reports on why oil prices might surge.