Pizza Hut and security firm G4S are confident their HR procedures are robust despite being fined for employing illegal workers.
Both firms insisted the incidents were isolated after the UK Border Agency fined more than 1,000 companies for employing unauthorised workers – the vast majority being in the restaurant and takeaway sector.
Pizza Hut branches in Reading and Hounslow had an illegal worker each, as did G4S.
But a spokeswoman for Pizza Hut said: “This particular incident took place almost a year ago at one of our franchised stores. We have since ensured that all our franchisees have reviewed their processes, to prevent this happening again.”
A G4S spokesman said: “We can confirm that we were issued with a financial penalty in November 2008 after an enquiry ruled that an officer was working in excess of the 20 hours a week permitted for a resident on a student visa.
“This was an isolated incident and we have updated our IT systems to ensure this situation is not repeated.”
Restaurant chain Chez Gerard and a BP garage in Southampton were also fined for employing an illegal worker each.
An average of £5,000 per illegal worker was paid out by firms – half the maximum possible penalty, introduced in February last year.
The UK Border Agency revealed 1,161 firms have been fined nearly £10m for flouting employment laws in the past 16 months.