Britain’s warning to potential suitors of BP is a sign of the oil major’s vulnerability to a takeover bid and that a more politically palatable tie-up with Royal Dutch Shell no longer seems to be an option, banking and industry sources said. Despite championing a laissez-faire policy towards takeover deals, Britain has always had a special interest in BP, dating back to the creation of the company via an unusual government investment master-minded by Winston Churchill. But in the past when the company has looked vulnerable, there was always the prospect that Anglo-British peer Shell could act as a “white knight” and agree to a merger deal that would preserve British interests. With Shell now tied up with a $70 billion takeover of BG, that seems much less likely, prompting the outgoing British government to break cover and say it would oppose any bid for BP. […]