It’s not up to retail investors to revive the London Stock MarketRetail investors will not be enough to fix the UK's capital marketsThe British Isa has once again reared its head. “Do we really want to be lowering the cost of capital for American companies by giving a tax incentive for investors in Isas?” Brits contribute in the order of £30bn a year to stocks and shares Isas, much of which doesn’t go into UK equities. It’s hardly going to move the dial, in terms of UK cost of capital, if you get a few extra billion into London stocks. And stocks and shares Isas have been a great success over the last 25 years.