The Czech billionaire vying to buy Royal Mail should face a fit and proper person test, the architect of the postal service’s privatisation has said. Sir Vince Cable, who oversaw Royal Mail’s stock market float in 2013, said ministers had “good grounds” to investigate Daniel Křetínský if he tabled a firm takeover bid for the company. He added that any deal with Mr Křetínský, the co-owner of West Ham FC and who is known as the “Czech sphinx”, should also be reviewed under tough new national security laws. Sir Vince told The Telegraph: “I don’t think one should be nationalistic about this but Britain has, more than any other major G7 country, been open to the takeover of utilities and I think the public mood has probably gone too far, which is why I suggest that applying the screening test is something that should be done. “There are two public policy issues. One is the fit and proper person test – it’s quite an important institution. And secondly this new screening system that the Government has introduced that is allegedly national security but is actually screening out desirable and undesirable mergers. “So it seems to me that there’s good grounds...