Animal cruelty allegations against an East Lothian lab have been thrown out following a Home Office investigation.
Inveresk Research, which does tests for some of the world's biggest drugs companies, had been accused of breaching its animal testing licence.
A report by animal rights group, Animal Defenders International, included images of dogs with masks over their noses and a monkey clamped down.
However, the Home Office found the tests being carried out were licensed.
Much of the information requested by ADI about the licences was exempt from disclosure under the Freedom of Information Act, because of the threat from radical groups.
Jan Creamer, chief executive of ADI, claimed the Home Office was not given details of individual tests carried out on animals.
"The Home Office does not retain the details of the individual tests. The licences awarded to Inveresk and others are for tests on groups of chemicals. They do not have exact details of each test.
"These are kept by the laboratory and are the property of the lab and the client. We think this is entirely unsatisfactory.
"The public would be amazed that the Home Office has no details of animal tests, and would not see the details of tests such as the ones we have described.
"The public is always given the impression that animal tests in the UK are tightly controlled, but this is not tight control in our view."
American company Charles River Laboratories, which merged with Inveresk last year, insisted when the report was published that it was committed to humane animal research, and that the company adhered strictly to codes established by the world's leading regulatory authorities.
A Home Office spokeswoman said: "Animals Scientific Procedures Division found no evidence of compliance problems with the Inveresk studies licensed under the Animals (Scientific Procedures) Act 1986. "