From a trusted mailing list:

Saturday, 12. January, was the latest in a line of successful airport actions at Heathrow Terminal 4. Supporters of a mother and her two children, due to be removed to South Africa, handed out leaflets to the passengers detailing the plight of the family and asking them not to take their seats. They also spoke to the cabin crew and the pilot.
Pilot and crew were astounded to find they had deportees on board and refused to carry them.
Airport officials called the police and had the protesters
removed from Terminal 4. Two of the demonstrators were arrested, but later released without charge.
Over the last fortnight there has been almost daily protests at Heathrow Airport's Terminal 4 against removals. On all occasions where the pilot and cabin crew have been told that they have a 'deportee' on board, they insisted on the person being taken off.