He added: “At the moment we’re in the right place but there will be pushback from some elements of government.”
The government’s commitment to maintaining high food and environmental standards in post-Brexit free trade deals may also be “an area of lively debate over the coming weeks”, he said.
“Do we have an absolute red line saying we're not going to allow stuff to come into this country that would undermine our environmental standards our animal welfare standards, for example? My view is that we need to be absolutely rigid about that. There will be other people in the government who will take a different view,” he added. “I hope we end up in the right place.”