When the Boat Comes In S04E07 - The Bright Young Things

Having made money from his deal with the oil company, Jack is mixing in London high society. His land agent, Frank, asks Jack to broker the sale of an expensive emerald necklace to Morty Black. The necklace is owned by Philip Martin whose sister, Jane, is unbalanced and would kill to get the necklace for herself. The sale goes ahead. When Jack learns that Morty paid off the mobsters who were after him, he waives his share of the price.