A chilling remark exposing Karen Matthews' true feelings about her daughter's disappearance has been revealed by one of her former neighbours in a new Amazon documentary.

Matthews, from Dewsbury, Yorkshire, was dubbed 'Britain's worst mother' after engineering a plot with Michael Donovan, the uncle of her then-boyfriend, to kidnap nine-year-old Shannon.

The pair held the young girl captive for 24 days in a plot to claim a £50,000 reward. Her captivity began when Donovan enticed the nine-year-old into his car on the way home from a school swimming trip on February 19, 2008.

Police launched a £3.2million search for missing Shannon, only to discover that she had been tied up in Donovan's home.

The youngster had been sedated with the adult sedative temazepam - not only during the kidnap but for up to 20 months prior - and provided a list of rules on how to behave to avoid being detected.