Novartis’ general counsel Felix Ehart has announced that he will resign after revelations that he was a co-signatory on a controversial contract with US president Donald Trump’s personal lawyer Michael Cohen.

The $100,000-per-month contract between Novartis and Cohen’s Essential Consultants was approved under former chief executive Joe Jimenez in 2017 as a bid to gain insight into US healthcare policy under the new administration.

Novartis ended the contract this year.

“Although the contract was legally in order, it was an error,” Ehrat said. “As a co-signatory with our former CEO, I take personal responsibility to bring the public debate on this matter to an end.”

In a statement Novartis added that the Board of Directors and the Executive Committee have “the greatest respect” for Ehrat's decision to step down.

Jörg Reinhardt, chairman of the Board of Directors said: "I appreciate Felix's decision even as we regret his departure. We thank him for his contributions to the company as General Counsel.”

This is the latest in a string of reputation blows to the company, which has also faced allegations bribery in Greece and South Korea and data-tampering in Japan.

Shannon Thyme Klinger, currently chief ethics, risk and compliance officer, will replace Ehart as group general counsel, effective 1 June 2018.