Boris Johnson, Britain's prime minister, has been slammed as a "misguided high-stakes gambler" for risking the futures of the millions of Britons living in the EU and EU citizens living in the UK.
The damning indictment comes from Nigel Green, founder and CEO of deVere Group. It follows Luxembourg's PM, Xavier Bettel, lambasting Boris Johnson over the "nightmare of Brexit" as he stood next to an empty podium because Mr Johnson scrapped a press conference when he was booed by protesters.
"Our people need to know what is going to happen to them in six weeks' time. They need clarity, they need certainty and they need stability," Bettel said.
Johnson must stop his high-stakes gambling of these people's futures. It is misguided, risky and cruel."
The deVere CEO said: "The millions of British expats in Europe and the EU citizens living in the UK are amongst those who will be disproportionately adversely affected by a no-deal Brexit.
"Boris Johnson must stop his high-stakes gambling of these people's futures. It is misguided, risky and cruel."
He continues: "While Mr Johnson has stressed the rights of EU citizens living in the UK in the case of a no-deal Brexit will be protected, the EU cannot give such a guarantee for UK citizens because it is up to individual member states.
"It's all likely to depend on reciprocal agreements between the UK and member states of the EU27."
Green added: "The Withdrawal Agreement has failed to get UK parliamentary approval and a no-deal Brexit on 31 October seems an increasingly real possibility.
"Jumping off the cliff-edge on Halloween, a number of things would change. For example, a no-deal would mean the current reciprocal healthcare, shared by the UK and the EU27, would no longer apply."
"How can Boris Johnson provide the clarity, certainty and stability that the Luxembourg PM demands for the millions of expatriates in the EU and in Britain?
"He must stop wasting more time and get on with seeking a deal that gets through Parliament".
The deVere boss added: "In addition, the UK parliament must reverse the law that denies British citizens the right to vote after leaving the UK for more than 15 years. The UK is the only country with the G7 that has this archaic ruling of giving its own citizens a shelf life of 15 years should they choose - as is their right - to live, work and/or retire abroad.
"This means that hundreds of thousands of Brits living in Europe couldn't vote in the Brexit referendum.
"Maybe the result would have been different; maybe not. But either way, those whose futures are reliant on it deserve a vote."
Green concluded: "While Boris gets booed and bottles it in Luxembourg, and continues to play for political gains, hanging in the balance are the futures of millions of expats."