Charm production in hadronic W decays at LEP                                   
  
Using approximately 240 pb-1 of data collected at centre-of-mass energies      
around 183 GeV and 189 GeV with the OPAL detector at LEP, a sample of          
W-pair events is selected. A value of the partial decay width for W->cX        
is extracted from jet properties, lifetime information, and semi-leptonic      
decay products of the charm quark. This measurement allows a direct test       
of unitarity of the CKM matrix in three generations within the framework       
of the Standard Model. Furthermore, the measured value can also be used to     
determine the value of Vcs using the measured values of the other CKM          
matrix elements.                                                               
  
 Parallel session :5                   
 Plenary  session :6a