Lord Alton of Liverpool, an independent peer, said embryonic stem-cell research had not been able to produce a single medical treatment “whereas pluripotent stem cells have the versatility”.

“The issue was always with the versatility,” he said. “In this country we have destroyed or experimented on over 200,000 human embryos with no cures forthcoming. I have argued throughout that it was unnecessary but also pointless to use embryos.”

He said it was “emotional blackmail” to imply that anyone who opposed the “destruction of human embryos” was “standing in the way of science”.