The bull's owner, Ken Jackson, has been told a court order protecting Boxster from slaughter has expired and the Government's vets will be coming for the animal on January 19.
The news came the day after he heard that the rest of his herd had been declared free of TB, for the second time since he was forced to sacrifice several animals last March.
The vets have twice retested every animal except Boxster.
They say Boxster has to go because he appeared to be TB-positive in the first place and they are worried about setting a precedent by agreeing to a re-test of a condemned animal.
But the Jacksons are sure a mistake was made and the mighty British Blonde bull is still healthy, although confined to a quarantine paddock at Stubbs Walden, near Doncaster.
Mr Jackson said Defra's Animal Health division, in Leeds, had told him he could get an all-clear for his farm if he agreed to let Boxster go.
"If they prove he has TB, I will do the job for them," he said. "But everybody tells me that if he had TB, he would be showing symptoms by now."
Meanwhile, his lawyers will apply next week for another injunction to keep Boxster safe until there has been a full judicial review of the grounds on which Defra condemned him.
The family switched legal representation and it has only just been discovered that the last injunction ran out when a written application for judicial review was rejected at the end of October. Now, they must apply for a live hearing of their case, in court.
A Defra spokesman said the decision to slaughter was made in the light of concerns about the disease risk of Boxster's presence as a TB reactor.