John Edward Locke and his younger brother James Harvey took over the distillery in the 1880s. This was the golden age for Locke’s distillery, reaching peak output in 1883. During this time, the plant was upgraded and extended, a steam engine was installed, and new buildings and offices were added. At the height of production, 120 people were employed (compared to 42 in 1873).
In 1890 John Edward Locke married the young Mary Edwards who became known as ‘Muds’ Locke because of her hunting exploits. They had two daughters, Sweet and Flo, but the marriage ended in divorce as Muds was not the most devoted wife. A settlement of £600 was made in 1896 and Muds and the children moved to a fine house in Ballinagore. Muds worked for the Red Cross in France during the war and subsequently became the commandant of the Red Cross Hospital in Mullingar. John Edward continued to live a more spartan existence in the old family home beside the distillery, where he kept a close eye on the day-to-day running of the business.
James Harvey Locke, on the other hand, remained at the family home in Ardnaglue, leading a more stylish existence. He indulged in the quintessentially British sporting and social affairs such as hunting, horse racing, polo, and cricket. He kept his own pack of harriers for hunting and maintained a racing establishment at the Curragh, where numerous races were won in the Locke colours. He also rode many winners locally at the Kilbeggan Races, played polo in Mullingar, and established a cricket club in Kilbeggan. James Harvey never married, but he had a long-standing love affair with Muds’ sister, Florence, to whom he left the farm at Ardnaglue.
John Edward died in 1920, leaving James Harvey to run the distillery. Sales had dropped markedly as 81% of the whiskey output in Ireland had shifted to column stills, producing spirit quicker and more efficiently than Locke’s pot stills. Amid a perfect storm of external interference, including the US Prohibition, the distillery ceased operations in 1924 and began to sell off the stock. Most workers were dismissed, and the future of the distillery looked bleak. James Harvey died in 1927, and ownership passed to John Locke’s granddaughters, Mary Evelyn and Florence Emily.