Billionaire Mike Ashley has been revealed as the biggest employer to use the soon-to-be illegal “zero hour” contracts that potentially stop the 20,000 part-time staff at his retail empire getting a second job. The policy was described as unfair and exploitative by MPs and campaigners and means 90 per cent of workers at his Sports Direct stores have no guaranteed working hours and must seek permission from management to work elsewhere.The revelation comes a year after senior management at Sports Direct took share option bonuses worth three times their pay...The Government is seeking to ban such working conditions. Ministers estimate some 125,000 workers will benefit, meaning Sports Direct staff account for almost one in six of the entire workforce the Government wants to help.