British Airways Boeing 747-436 G-CIVV operating BA57 London Heathrow – Johannesburg (depart London Heathrow 14th January) turned back over Africa and diverted to Barcelona this morning and then returned to London Heathrow. The initial diversion was due to a passengers with a medical issue, although it is not clear why the diversion was not to an African airport. Having gone to Barcelona crew had sufficient hours to return to London Heathrow but not to set off again for Johannesburg.