Tesco may have to appoint an auditor to assess its ethics in trading with suppliers, after a private investor obtained enough support for the idea to push it on the company's annual meeting agenda.

Secretary of the campaign group War on Want, Ben Birnberg, proposed the idea ahead of Tesco's annual meeting in June.

He called for the company to 'take appropriate measures to be independently audited' to ensure that workers of supplier factories have 'decent working conditions, a living wage, job security, freedom of association and collective bargaining,' the Telegraph reported.

Birnberg said his initial proposal had been rejected so he gathered support from more than 100 others who each had an average of at least 2000 shares, a requirement of the Companies Act.

'In fact I've got six times that – there has been a real groundswell of support,' he said.

Birnberg will deliver documents to Tesco ahead of the deadline on Friday for items to be included on the agenda of the June 29 annual meeting.

Tesco said: 'We will give full consideration to any submission he or any other shareholder might make. Fair treatment of workers in our supply chain is extremely important to us.'

Further reading:

Investor forces ethics on to Tesco agenda

Investor puts ethics on Tesco agenda

Small suppliers hit by retailers' 'shocking' late payment record