The U.K. is facing a grim future after Brexit because of the failure of its politicians to govern responsibly, the former chairman of insurance market Lloyd’s of London wrote in a letter to the Financial Times.

“Never in over 50 years of working life have I seen the U.K. facing such an abject future,” said John Nelson, who said the situation was”caused by the complete failure of our political establishment to govern, to communicate clearly with the public and most importantly to be honest with the electorate.”

He said that leaving the EU, even on the basis of the position recently agreed by the U.K. government, would lead to it “becoming a much poorer country than anybody was led to believe during the appallingly conducted referendum campaign.”

The impact on the economy, employment and the provision of public services such as agriculture, health care and air transport have been underestimated, he argued, lost amid a lack of cooperation between MPs.

Without naming anyone, he criticized the “ambition and vanity” of senior politicians, who he said aren’t acting in the best interests of their country. He also criticized a “silent majority” of others in the major parties who seem terrified of raising their views, and called on British businesses to speak up to give their account of the true consequences of Brexit.

“Personal experience tells me that negotiating overseas rights is a long and painful process,” he said. “As a small economy, the leverage we have is limited and far less than operating as a trade bloc, which is the EU.”