The late Cilla Black's ''darkest fear'' was not being able to enjoy a good quality of life.

The English singer tragically passed away in August 2015 after suffering a fall at her home in Estepona, Spain, and though the 'Blind Date' host felt ''incredibly young'' at heart, when she started to battle with various ailments, such as arthritis and loss of hearing, the thought of ''compromising'' certain aspects of her life and becoming a ''shadow of her former self'' weighed heavily on her mind.

Speaking to The Mail On Sunday about his parent, Robert said: ''She wanted to go on doing what she wanted to do. She'd never had to diet, so she was suddenly having to do certain things just to maintain the way she lived. She was a bit offended by that. She was someone who lived life fully - the amount of shows she did was incredible - but she wasn't used to compromise.

''She was in a great deal of pain after developing arthritis in her right hand, which meant she had to have a bone removed below her thumb and forefinger. It affected her ability to grip and although the operation would do the trick, she resented the nine months it would take to heal.

''In her heart and in her head, she was incredibly young so I think she found it all difficult.

''Then it was discovered she had a form of arthritis in one knee. She managed to avoid a knee replacement by the use of medication, but she had stoically put up with it for too long which resulted in quite a bit of muscle wastage. In truth, she wasn't the best patient.

''Her mother suffered from osteoporosis and in old age, slowly became a shadow of her former self. That was my mum's darkest fear, that the same thing would happen to her. She was getting a bit worn down by ill-health, even though she still had that incredible poise and dignity''.

And Cilla - whose full name was Priscilla White - refused to admit she was going deaf and her visibility was deteriorating, so she would refuse to turn up the volume on her hearing aid, and even had her cataracts removed.

Robert said: ''She couldn't be bothered with them. Her solution was to turn up the volume on the telly. And she also had cataracts removed. It seemed that as soon as she'd turned 70, there was always something else.''

But Cilla also ''hated the thought'' as she got older she would have to trade in her high heels for flat shoes.

Robert added: ''For example, most women, once they hit a certain age, find they can't wear high heels. That was a major deal for my mum. She hated the thought that she would have to wear flat shoes.''

Although Robert and his other siblings, Jack and Ben, as well as Cilla's celebrity friends, including Sir Cliff Richard and Paul O'Grady, were left heartbroken when they heard the 'You're My World' hitmaker had died, Robert believes his mother would have wanted to pass when she did.

He said: ''So as much of a tragedy as her death was, I think that in some respects she would have chosen to go when she did because for her it was all about having a quality of life. It wasn't the length of time - it was being able to do what she wanted to do.

''Obviously I miss my mum and I regret the fact that she's not here. But I don't have any other regrets. I don't think she could have lived her life in any other way.

''She always did it on her terms, rightly or wrongly. And that was right for her.''