Carsten Kengeter, the Deutsche Börse chief executive who would lead the entity created by a merger with the London Stock Exchange, denies allegations of insider dealing

Theresa May has been urged to “protect” the City by blocking the planned £21 billion merger of London Stock Exchange and Deutsche Börse.

The prime minister was warned that the deal was “not in the public interest” and would be “detrimental” to the UK. Anne Marie Morris, the Conservative MP, added that it “flies in the face” of Mrs May’s pledge to create a “proper industrial strategy” that defends British companies from overseas acquisition.

On the eve of a parliamentary debate this afternoon, Sir William Cash, the veteran Eurosceptic Tory backbencher, suggested that there were “question marks” over Carsten Kengeter, the Deutsche Börse chief executive who would lead the merged entity. Mr Kengeter is facing a German police investigation over alleged insider dealing. He denies