The 65-year-old was staying at her holiday home in Morocco when she passed away. Her agent has said she'd been ill for some time.
In 2009, Hilary suffered a stroke following a tummy tuck, losing her peripheral vision and sensation in her left arm.
She made her fortune after founding the haulage company Pall-Ex in 1996,
Her television career included "Dragon's Den", "The Secret Millionaire" and "Loose Women".