British trade negotiators begin a marathon of talks on Monday in Brussels aimed at forging a new post-Brexit relationship with the EU, but the two camps have drawn red lines that remain far apart. The EU’s chief negotiator Michel Barnier and his UK counterpart David Frost will lead the talks, which would be held over several weekly rounds in Brussels and London. The negotiations start just over a month since Britain left the EU, and are meant to wrap up by the end of this year — an exceedingly tight timeframe that few see as feasible for anything but a bare-bones accord.