The music mogul and his siblings lost Julie at the start of July (15), aged 89, and Cowell scrapped auditions for The X Factor to mourn her death.

Tony, a journalist, has now revealed how Julie's health deteriorated after she suffered a stroke in October (14) and the family was both heartbroken and relieved when she passed away.

He tells Britain's Best Magazine, "As Simon said the night she died, 'Mum is at peace now. We will never forget her and how much she loved us'... No matter what age you are, it's devastating to lose your mother. From the moment our mum, Julie, suffered her first stroke in October last year, it was clear she was unlikely to recover. She was 89, frail and had quickly slipped into unconsciousness. To see her in hospital was heartbreaking. She didn't know who we were and she never really woke up again.

"When I got the phone call she had died, I felt an immediate sense of relief - we all did, as we wanted her to go with some dignity... Today, I feel for my family, including Simon, who must live out his grief in the glare of the spotlight... That's not easy, but the Simon I know and love will come through. Like Mum, he's a fighter- he never gives up... Mum's death hit us hard, but I know she'd want her boys to move on... I only wish (Simon's) baby Eric could have had more time to get to know how wonderful his grandmother was."