Deliveries of imported chemicals for clean drinking water could be caught up in border chaos in the event of a no-deal Brexit: AFP/Getty Images

The prospect of Britain running out of clean water within days of a no-deal Brexit reportedly convinced Michael Gove to back Theresa May’s deal.

Ministers were warned that leaving the EU without a deal could spark a clean water shortage as the chemicals used in purification are imported to the UK from Europe, according to the Mail on Sunday.

Deliveries of the chemicals could get caught up in weeks of border chaos in the event of a no-deal Brexit and the chemicals cannot be stockpiled and usually arrive “just in time”, the newspaper reported.

It was citing leaked Whitehall contingency plans named Operation Yellowhammer that have been briefed to ministers including the Environment Secretary.

View photos Environment Secretary Michael Gove (Photo: Jack Taylor/Getty Images) (Getty Images) More

As a result, Mr Gove is said to have judged that no deal is not a viable exit route. The contingency plans, described by a source as “Project Fear on steroids”, indicate that if water plants run out of the chemicals needed they “would probably need to stop the water supply to all their customers”.

Schools and office buildings could be forced to close and householders could face a shortage of drinking water, inability to flush toilets, cook, wash clothes or keep themselves clean, the contingency plans said.

Tap water contains chemicals including liquefied chlorine, sodium silicofluoride, aluminium sulphate, fluorosilicic acid and calcium hydroxide.