The number of US-style sweet and souvenir shops blighting Oxford Street has dropped by nearly a third, according to Westminster Council.The local authority has accused some of the businesses of fleecing the taxpayer with £8m of tax evasion and of “lowering the tone” of the capital’s most famous shopping street.Three sweet shops have been wound up for non-payment of rates in recent weeks, officials said, while two companies have coughed up £250,000 in business rates arrears to avoid court action.“For unscrupulous sweet shop traders on Oxford Street, life is becoming increasingly sour,” said the council’s leader, Cllr Adam Hug.He said legal action and Trading Standards raids have reduced the number of shops from 30 to 21.