leonie granger , 25 , has been jailed for 16 years for luring gambler to death .
convinced mehmet hassan , 56 , she was interested in him at mayfair casino .
went to his flat and let in boyfriend kyrron jackson and nicholas chandler .
they kicked mr hassan to death and stole some of his gambling winnings .
granger convicted of manslaughter and two men found guilty of murder .
judge william kennedy today described the attack as ` pitiless and wicked '