LONDON, Dec 18 (Reuters) - Britain wants a free trade deal with the European Union but is prepared to walk away from talks without one unless the bloc changes its stance and respects British sovereignty, Britain’s schools minister said on Friday. “It is a very serious situation. We will test every route to seeking a free trade agreement with the European Union, but we cannot do so at the expense of our national sovereignty,” Nick Gibb told Sky News. “We want a free trade deal. The EU will have to move if we are going to secure that deal... We’ll test every route, but we are prepared for a no free trade deal arrangement” (Reporting by Alistair Smout; Editing by Alex Richardson)