Britain should be made to suffer as it leaves the European Union in order to stop other countries following it, the man who drafted Article 50 has said.

Giuliano Amato, a former Italian Prime Minister, said that Brussels should offer no concessions to London during Brexit negotiations, adding: “When it comes to the economy, they have to lose.”

Mr Amato was one of the main authors of the proposed European Constitution, which was later turned into the Lisbon Treaty after it was rejected by voters.

“I wrote Article 50, so I know it well,” Reuters quotes him as saying. “My intention was that it should be a classic safety valve that was there, but never used. It is like having a fire extinguisher that should never have to be used. Instead, the fire happened.”

Mr Amato, who served two brief terms as Italian Prime Minister from 1992 to 1993 and 2000 to 2001, said the UK’s vote to leave the EU was a “disaster”, and urged leaders from other member states never to offer their own referendums on membership.

“If another leader is as mad as Cameron to offer a referendum on EU membership, for example in Holland or Austria, there is a risk (they would vote to quit),” he said.

As an added disincentive, he called for Brussels to make Brexit “especially tough” for the UK, and even raised the possibility it could force Britain to reconsider.

“Don’t give Britain the possibility of thinking that Brexit is a better way of doing what they have always done, grabbing what suits them and opting out of what they don’t like. Brexit is a total opting out. They know this very well.

“The more they realise that they are losing, then the more chance there is that in 2020 someone will do something about it,” he added.

If Brexit talks can be dragged out beyond 2020, there is a possibility that a pro-EU party could win Britain’s General Election that year and undo last month’s referendum result, Mr Amato added.

“I hope that the negotiations are dragged on so they won’t be wrapped up by 2020. (Prime Minister) May wants to wrap things up by 2019, but it will be easy to prolong matters,” he said.

He acknowledged, however, that this was an “absurd hope”.

His comments come as bookmakers slash the odds on the British government never invoking Article 50. Sky Bet puts the odds on Brexit never happening at 2/1, the same as Article 50 being invoked early next year.