Martin Winterkorn, Volkswagen's former chief executive, received emails about its diesel emissions crisis over a year before it became public, the company has admitted.

Mr Winterkorn, who resigned over the scandal in September, was also present at meetings where the issue was discussed last July, weeks before the issue become public on September 18th.

However, the company insisted there was no evidence Mr Winterkorn read the emails or participated in the discussion at the periphery of the meeting on Volkswagen’s cheating in emissions tests. It added that the issue “did not initially receive particular attention” from the company’s management. Mr Winterkorn could not be reached.

VW made the admissions in a statement announcing it was mounting a vigorous defence against legal action by a group of shareholders. They had claimed in the action, filed in Germany, that the company failed in its legal duty to notify capital markets about important developments promptly.

The statement calls the shareholders’ legal action “without merit”.

The company has admitted since the US's Environmental Protection Agency first made the scandal public that more than 11 million diesel-engined vehicles worldwide were fitted with "defeat devices" to circumvent emissions tests. The devices detect when the vehicle is being tested and switch on instruments to reduce nitrogen oxide emissions.

The company could face fines of tens of billions of dollars in the US over the cheating and faces billions of euros of costs to fix the vehicles.

More than 100,000 Irish cars are affected.

Mr Winterkorn insisted when he resigned over the issue that he had become aware of the problems only just before they were made public and that he knew of no wrongdoing on his part.

– (Copyright The Financial Times Limited 2016)