Supermarket chain says it has apologised to 140,000 workers who were mistakenly paid below the national minimum wage Tesco is to reimburse 140,000 current and former staff members a total of £9.7m after payroll errors meant they were paid below the national minimum wage. Britain's biggest supermarket chain said the majority of workers affected would receive up to £40. Tesco employs 320,000 people in the UK.