Earlier this week, the company said it had improperly inspected some of its train-carriage air conditioners and brake compressors.

The earliest of the fabricated inspection documents dated from 1985.

“I deeply apologise to everyone,” CEO Takeshi Sugiyama told reporters.

“We reached a conclusion that I should step down from the president post and we need to work hard to regain trust under a new management,” he said.

Mitsubishi Electric is one of Japan’s largest general electric manufacturers, producing a wide range of products from home appliances to heavy machinery and defence equipment.

Trade and Industry Minister Hiroshi Kajiyama said the scandal could “damage trust in Japan’s manufacturing considerably”, reported public broadcaster NHK.

Mitsubishi Electric said it would conduct further investigations in all sectors, pledging to release a report on the issue in September and to take preventive measures.

But it insisted that the concerned products did not pose any safety risk.