Tesco is facing the UK's largest ever equal pay claim and a possible bill running to £4bn.

Thousands of women who work in Tesco shops could get back-pay totalling £20,000 if their legal challenge demanding parity with men who work in the firm's warehouses is successful.

Tesco said it worked hard to ensure all staff were paid "fairly and equally".

Pam Jenkins has been working for Tesco for 23 years.