Mark Watson, who represented Tesco in court said the company had invested in "procedures and systems" to correct the problems and insisted the problem was with local management.
A shopper first noticed a mouse in the store in March last year, and reported it to Westminster Council.
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The victim reported Samantha Watt to police in July after she discovered the photos had been put up on her Facebook page.
The roof and floors collapsed during the blaze at the property, one of Britain's finest Palladian mansions.
The former Tottenham and Arsenal player made his feelings clear after visiting the Cambridge Street Cafe in south London.