If you want to protect a British company from being bought by a foreign country (which is a pretty stupid thing to want in the first place - if the British people thought it was worth more than that then they'd be buying the shares themselves rather than selling it off. They clearly think it's smarter to sell it off and invest the money elsewhere) - then the way to do it is through _law_, not preventing one of the many, many banks in the country from getting involved.
You're just attempting to point-score, which is childish, immature, and frankly beneath you.
Stop it.