The couple now face further legal action and could be charged with contempt of court after their decision not to attend an appointment yesterday at Great Ormond Street Hospital in London.
Camden Council, which initiated the legal moves after failing to persuade the girl's HIV positive mother and the father, who is clear of the virus, to have her tested, said it would give the parents one more chance before taking the case back to court. In a statement issued last night, the authority urged the parents to consider their position very carefully.
There are fears that the five-month-old child has been taken abroad. Camden Council, which successfully applied to the court for an order that the child should be tested under the 1989 Children Act, admitted it had no idea where she was.
The girl's parents, from north London, are believed to have gone into hiding just days before they were due to start their appeal against the order.