The expansion followed last week's interim results when it shattered the£1 billion barrier for half-year pre-tax profit for the first time.
According to a study by retail consultant CACI, the only areas in Britain where Tesco does not make any money are Harrogate, the Outer Hebrides, Lerwick in Shetland and Kirkwall in the Orkney Islands.
Meanwhile, the supermarket chain was caught in the middle of a child labour row after accusations were levelled at two of Tesco's Bangladeshi suppliers on Channel Four News last night.
An undercover investigation by the programme into four factories found that children said to be as young as 12 were working at Harvest Rich and Evince Group - both of which supply the UK chain.
The minimum age limit for workers supplying clothes to Tesco is 18.
A Tesco spokesman said: 'We are very disappointed that Channel 4 has waited three months to bring this matter to our attention. We abhor child labour and feel that Channel 4 had a duty to alert us earlier if these allegations are true.
'As soon as they did bring them to our attention, we immediately carried out unannounced inspections of the sites they say they visited and, despite rigorous investigations, have found no evidence whatsoever of underage workers.'
He added that two of the factories, one belonging to Evince and one to Harvest Rich, were producing Tesco clothing without the company's knowledge and had since ceased production.