'Horsemeat Banquet', a BBC documentary revealed that even scientists were baffled after tests on an Indian lamb curry showed no trace of lamb, chicken, pork, mutton, beef or even horsemeat.
It was, however, ruled out as being human flesh.
Experts examined a range of takeaway meals in London as part of the documentary aired here yesterday.
When the presenter, Rick Edwards suggested that the unknown meat found in Indian dishes could be of cat or dog, nutritionist Surinder Phull said that "any animal with flesh similar to lamb" could have been used.
"At this moment, the lab is unable to identify exactly which animal this meat came from," a spokesperson for the show said.
Other tests revealed that so-called "beef" in some popular Chinese dishes was actually made entirely from chicken blood and a little chicken.
Indian and Chinese meals are the most popular takeaway dishes in Britain and the latest discovery led to renewed calls for rigorous tests on various meat being served across the country.
Hindu groups based in the UK have called on the government to enforce stricter disclosure norms after it emerged earlier this month that more than a third of curry restaurants in Scotland were serving a much cheaper beef in place of lamb.