The Green Party accused the Government of “changing the rules” and demanded the “unscientific farce” cease immediately.
Asked on BBC’s Spotlight programme in the West Country whether he was “moving the goalposts”, Mr Paterson said: “That’s not right, the badgers have moved the goalposts.”
He added: “You are dealing with wild animals. It is a wild animal subject to the vagaries of the weather, disease and breeding patterns.”
Green Party leader Natalie Bennett claimed the trial was “shambolic” and “inhumane” and failed to meet its objectives for the number of badgers to be killed.
She said: “Even after the figures for the total badger pollution was convenient slashed, we know from on-the-scene observers that at least some badgers were killed after being cage-trapped, rather than shot in the open.
“Mr Paterson, outdoing himself even by his usual standard of argument, claimed that ‘badgers had moved the goalposts’.
“In fact it’s he who has kept changing the rules, desperately clinging to a failed policy rather than developing a proper, thought-through policy to deal with the problem of bovine TB.
“Once again this government has failed to adopt evidence-based policy, preferring instead the scribbled on the back of an envelope, ignoring the facts approach.”