Clare Balding introduces live coverage of the Challenge Cup semi-final between Leeds and Castleford at the Keepmoat Stadium in Doncaster. Leeds have been Super League's Grand Final winners three times in the past four years but haven't won the Challenge Cup since 1999 and will be keen to get back to Wembley after a disappointing display in last year's final when they lost to Warrington. The Rhinos will be the favourites against Yorkshire rivals Castleford, who have not reached the Challenge Cup final for 19 years but who will be determined to give head coach Terry Matterson a memorable send-off with a visit to Wembley in his final season at the club. Show less