John Allan suggested Tesco could easily move its HQ out of London . Cameron has promised to renegotiate Britain 's membership of the EU . An in-out referendum on the outcome of the talks would be held by next month .
John Allan suggested Tesco could easily move its HQ out of London . Cameron has promised to renegotiate Britain 's membership of the EU . An in-out referendum on the outcome of the talks would be held by 2017 .