Dairy industry leaders have slammed Defra proposals to make the sector more environmentally friendly as "outlandish".

The first draft of the long-awaited Milk Roadmap, shown to a select group of stakeholders last week, suggests a wholesale switch to UHT milk and huge cuts to methane emissions from cows by 2020.

But industry leaders said there was no evidence such moves were needed, and claimed they would seriously damage farmers and processors.

"The industry is supposed to be in this as a partner, not in order to hear outlandish, dramatic suggestions with no evidence to back them up," said Dairy UK director-general Jim Begg.

The Roadmap's headline proposal is to raise UHT production from 5% of the milk market to 90% of it - which Defra claimed would cut waste. "There's no evidence to support that claim on waste," said Begg. "But there's overwhelming evidence that UK consumers prefer fresh milk."

The industry was willing to discuss greener packaging and less energy-intensive production, Begg said. But it could not consider making such dramatic changes for so little proven gain.

Another key plank of the draft Roadmap is a 60% cut in emissions from cows of the potent greenhouse gas methane, which has many times the warming effect of carbon dioxide.

The proposal has alarmed the NFU, which says such a reduction is only achievable by "killing a lot of cows".

"The only way to achieve that is to dramatically reduce the dairy herd," said dairy adviser Tom Hind. "Somewhere in Defra there seems to be a desire to reduce the consumption of dairy products and with it, the size of the national herd."

The Roadmap will be finalised in the run-up to a formal industry presentation in November. It is the prototype for nine other Roadmaps, including one for fish, which Defra is expected to draw up over the next 18 months.