london prime minister theresa may appoint top official brexit ministry eu adviser monday take tight control divorce negotiations britain try shift focus talk onto future relationship europe order strengthen cross-government co-ordination next phase negotiations european union prime minister appoint oliver robbins eu adviser cabinet office addition role eu sherpa government spokesman say statement robbins continue lead british officials negotiations work closely brexit secretary david davis spokesman say robbins 42 media report sometimes clash davis work brexit ministry since shortly set follow eu referendum june 2016. robbins replace permanent secretary brexit department second-in-command philip rycroft may whose position weaken lose govern conservative party majority june election criticize fail give clear instructions negotiate team foreign minister boris johnson accuse colleagues sunday backseat drive set vision brexit days may due give major speech subject sept. 22. move key individuals critical time add whole new dimension government chaotic approach brexit opposition labour party brexit spokesman keir starmer say real problem failure government confront difficult policy choices face bob kerslake former top government official tell bbc radio add time move odd could ... simple case prime minister want control influence process could clash personalities say worry signal send ... organization capability crucial time may due make speech britain future eu relationship ahead next round talk late month far negotiations term divorce make limit progress prompt warn eu start discussions post-brexit tie could push back october uk pm may tighten grip brexit talk appoint official eu adviser