Character mistake: Just after Necros has infiltrated the MI5 safe house, captured General Pushkin and then escaped, M says that thanks to Necros, there are "2 dead, 2 in hospital." However, in fact Necros killed or seriously wounded 5 people, not four. First of all he kills the cook by strangling him. Then he gives the butler incredible burns on his face before knocking him out and leaving him with serious injuries. Then, as Necros walks out of the kitchen, two MI5 agents confront him with guns drawn. Necros throws a milk-bottle grenade right at their feet. This certainly either kills or seriously injures both men (a grenade at your feet is pretty devastating). Then, Necros throws another milk-bottle grenade at an MI5 agent standing on the staircase, which explodes, either killing or seriously wounding him. That is 5 agents, not 4, who Necros has seriously injured or killed, not including the milkman he also kills at the start of the scene (who may or may not be an MI5 agent).
Character mistake: When the butler surprises Necros in the kitchen, he does not conform to standard emergency radio procedures. During an emergency, the emergency code word always stands right at the beginning of the message, precisely because the reporter might go off the air before he can finish his transmission. Rightfully, the message should read something like "Intruder alert, this is three-four, intruder in the kitchen, I repeat..." Of course this would have toppled the plot to no end.