The defence ministry carried out nerve gas tests on hundreds of guinea pigs and rats between 2012 and 2017 and testing is still going on, the AD said on Tuesday.

The animals – at least 200 guinea pigs and 200 rats – were exposed to deadly nerve gasses at the TNO Defence animal testing laboratory in Rijswijk over the five year period, the paper said. Animal welfare group Animal Rights has studied academic reports between 2003 and 2018 to find out more about the trials.

‘The animals developed runny eyes, shakes and could no longer walk,’ spokesman Robert Molenaar told the paper. ‘They either died during the experiments or were put down afterwards.’

A spokesman for the defence ministry told the AD the threat of attack by chemical and biological weapons is very real. ‘Think about the poison attack on the Russian double agents in England… or their use on a much wider scale in Syria,’ the spokesman said.

Although the use and storage of chemical weapons is illegal under international treaties, the TNO research institute can legally carry out experiments. These have included efforts to determine when best to apply antidotes, the spokesman said.

Frank Wassenberg, an MP for the pro-animal PvdD, said the tests are unethical and that he has written to defence minister Ank Bijlveld calling on them to be abolished.