The boss of Goldman Sachs has suggested a second EU referendum to confirm there is a consensus in the UK on the “monumental and irreversible” Brexit decision.

Lloyd Blankfein, in his latest intervention via Twitter on Brexit, said there was “lots of handwringing” from chief executives about Brexit and the “tough and risky road ahead”.

“Reluctant to say, but many wish for a confirming vote on a decision so monumental and irreversible. So much at stake, why not make sure consensus still there?”

Goldman employs 6,000 staff in the UK with its new headquarters due to be completed just as the country leaves the EU in March 2019. It is not clear how many staff will move into the new building, which is near Fleet Street in central London.

It is the fourth Brexit-related tweet by Blankfein, who has sent only 26 tweets from his account which has 70,000 followers.

The first Brexit intervention, a month ago, was sent as he was leaving Frankurt, the German city hoping to benefit from business that London risks losing as a result of Brexit. “Great meetings, great weather, really enjoyed it. Good, because I’ll be spending a lot more time there,” he said.

Less than 10 days later he sent a tweet of an aerial shot of the new £350m European headquarters the bank has under construction in London, with the words “expecting/hoping to fill it up, but so much outside our control”.

Two days ago, he tweeted from Paris where he said he was “struck by the positive energy” and remarked upon the “good food”.

Firms are warning the government that they will have to start implementing contingency plans by the end of March next year. Goldman’s plans include taking the top eight floors of a 37-storey block under construction in Frankfurt, which is expected to be ready for occupation in the third quarter of 2019. It could hold 1,000 staff – compared with the 200 it already employs in the German city.

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