A laid-off security guard who had spent his savings resorted to robbing a 73-year-old blind busker in a Mongkok subway, a court heard yesterday. Ng Hey-kwai, 51, whose attack on the woman was described as cowardly, pleaded guilty before District Court judge Alan Wright to one count of robbery and was jailed for three years and four months. 'Madam Mok Lai-to is 73-years old,' Judge Wright said of the victim. 'She's a female. She's blind. She supports herself by playing a musical instrument. 'She must be among the most vulnerable group in society and is entitled to protection from crimes of this nature . . . This is a cowardly attack on a weak old lady,' he said. The court heard Ms Mok had been playing the lute to earn a living in a subway under Soy Street and Nathan Road. On the afternoon of September 23, while she was performing, Ng approached her and pushed her back as he tried to snatch her nylon bag. Ms Mok put up a struggle during which her forehead was hit by the lute. Ng then grabbed the bag and fled. Two off-duty police officers heard the woman's scream and gave chase. Prosecutor Agnes Chan said one of them soon caught Ng. Ng's defence lawyer, Leung Man-wai, told the court Ng had spent two-thirds of his life in prison for his 25 previous criminal convictions but wanted to turn over a new leaf after his last release from jail in 1997. Ng had worked as a security guard but was laid off in August.