he is introduced in june 1988, as a character claiming to be from "walford investments", who tries to persuade james willmott-brown (william boyde) to let him buy into the dagmar. when willmott-brown refuses, he soon finds that his suppliers are refusing to do business with him. the bar's business suffers dramatically as a result. the firm financially ruin the dagmar for the purpose of drawing in its custom for their own wine bar, strokes, which is in fact a front for illegal gambling reluctantly run by den watts (leslie grantham). den later uses his firm connections to arrange for the dagmar to be firebombed in retaliation to wilmott-brown raping kathy beale (gillian taylforth), which angers mantel and the firm's bosses, the unseen mr. vinnicombe and jack dalton (hywel bennett). mantel and vinnicombe are good friends, and mantel reports directly to him. mantel later establishes the portakabin office on albert square as a base of operations for "walford investments".