This move follows an investigation into two of the UK’s largest suppliers of rolled lead to roofers – Associated Lead Mills Ltd (ALM) and H.J. Enthoven Ltd (trading as BLM British Lead).

The companies admitted last year to forming an illegal cartel and were fined more than £9m.

The CMA has now secured the disqualification of Jocelyn Campbell (BLM), and Graham Hudson and Maurice Sherling (ALM). All were directors at the time the illegal activity took place.

Campbell also sought to conceal his communications with competitor businesses by using a different mobile phone from his main one, in the period from December 2016 until the launch of the investigation in July 2017. This only came to light when the CMA seized the phone.

Sherling admitted to suspecting that ALM was breaching competition law and receiving competitively-sensitive information from a competitor (Campbell of BLM) but doing nothing to stop it.

Campbell will be disqualified for 6.5 years, Hudson for four years and Sherling for three years.

Michael Grenfell, Executive Director of Enforcement at the CMA, said: “It’s an important responsibility of company directors to ensure that their companies don’t engage in illegal anti-competitive practices, which can lead to higher prices for customers.

“The CMA has clear evidence that these directors either knowingly entered into illegal arrangements and communications, or were aware of them and did nothing to stop them.

“That’s why these measures are needed. This should be a message to all directors – if your company breaches competition law, you risk personal disqualification.”