She's never lost for words on the Loose Women panel, but at first, Coleen Nolan "bottled up" her heartache over her late sister Bernie's cancer. Hannah Stephenson finds out when the grief hit hardest.

She's an open book about family life, relationship issues and other heart-of-the-matter stuff as a regular on ITV's popular daytime show Loose Women.

Yet Coleen Nolan needed to put her most heartfelt thoughts on the death of her sister Bernie down on paper, namely in her second autobiography, No Regrets.

Much of the book is actually a moving tribute to Bernie, the positive, hard-working, party-going performer who lost her long battle with breast cancer last July, aged 52.

Meeting Coleen today, it's clear the wounds are still raw.

"I could have done a whole book just on Bernie. When you lose someone, you want to tell the whole world what they meant to you," she says solemnly.

Her older sister was diagnosed with cancer in 2010 and, after extensive chemotherapy and a mastectomy, thought she had beaten it. But it returned more aggressively in 2012.

"Sadly, when we did lose her, it was cathartic to write the book and get those emotions out, because we'd had to hold them in for so long. There were so many moments when Bernie didn't want people to know that the cancer had come back.

"She felt very guilty and that's why she didn't want people to know. She felt she'd let women down because she'd been this soldier saying, 'I'll beat this'. She didn't want other women who had found strength from her to lose hope."

What comes through in the book is Bernie's unequivocal positivity, her zest for life, setting herself goals even when she knew the cancer was incurable - but when she lost her ability to sing, Coleen recalls there were no more goals.

Yet even when Bernie was in agony, with sores on her feet and painful mouth ulcers from the chemotherapy, she would still go to work.

"She wanted to live life. When we said, 'Why don't you stop?', she'd say, 'What, sit at home all day thinking I've got cancer?'

"When she was on stage, cancer never entered her head. I hope I've adopted her work ethic."

While Bernie's type of cancer is not deemed genetic, it's an issue Coleen, 49, worries about all the time. Two of her other sisters, Linda and Anne, both had breast cancer and survived.

"It's a constant worry. I never stop checking myself and I go every six months to see the specialist.

"In my mind, if three of my sisters had it, it's got to be linked. It can't be coincidence."

Coleen is also concerned because some of the women in her husband Ray Fensome's family have had cancer.

Today, the family buy organic food and toiletries and avoid chemicals if they can.

Before Bernie's cancer returned, the Nolans had been planning a farewell tour for 2013. It had to be cancelled, and instead they gathered to say their farewells to their beloved sister.

Returning to the stage without Bernie is something Coleen cannot contemplate at the moment.

"There's been talk about the three of us - me, Maureen and Linda - doing it as a tribute to Bernie, but it just feels too soon for me. I can't imagine touring without Bernie. I don't know what part of that I'd enjoy. There would be a space that none of us could fill."

Today, it's mainly songs that trigger Coleen's grief, she reflects.

"The other day, on the radio, they played Run To You by Whitney Houston, which they played at Bernie's funeral, but sung by Bernie. I just wanted to sob."

During her sister's illness, Coleen found it difficult to concentrate when appearing on Loose Women. She admits she lost interest in the show because of the anxieties surrounding Bernie. To make matters worse, she saw a fortune teller on holiday who predicted her sister's fate.

"I was getting irritable before I left. We'd be talking about something and I'd just want to scream, 'It doesn't matter, because my sister's cancer has come back!' But I couldn't."

She left Loose Women in 2011 for two years, before returning last year.

"That whole two-year period was hard. I needed to be at home," she says. "Ray and I bottled things up. When Bernie was saying, 'It's not curable but it's treatable', I was thinking, 'Oh God...', especially after what the fortune teller had said."

The pressure affected her relationship with musician Ray, her second husband and father of her 12-year-old daughter Ciara, she admits.

"I don't think we sat down early enough and talked about it. It was always going to come to a head with me and Ray."

He had effectively been supporting Coleen's career for seven years before landing a job playing guitar for Rick Astley on Peter Kay's 2010 UK tour.

The job, which was all-consuming, ended up bringing out all of Coleen's insecurities and made her realise how much her first marriage to EastEnders actor Shane Richie (who cheated on her), with whom she has two sons, had affected her.

"Suddenly, Ray was involved with all these exciting people I didn't know, which was exactly what had happened when things started to go wrong first time around with Shane.

"It shocked me that subconsciously, I must have always held that insecurity. Then when Ray got this gig, it gave him a whole new lease of life and home life seemed to be getting in the way."

When things came to a head, she asked Ray to leave, which he did for a few days, until they had a heart-to-heart to sort things out - and have never looked back.

"It took us to a better level. You do have to work at relationships and we both realise that."

Bernie's death has brought them closer together, she reflects.

"It gives you a different perspective and it does change your priorities. What you thought was important really isn't. It's made me appreciate just being here."

Coleen, who lives in Wilmslow, Cheshire, recalls: "The time it hit me was New Year's Eve, when Steve [Bernie's husband] and Erin [daughter] spent New Year's Eve with me and Ray and the kids. It was the biggest time it hit me since her death. All of a sudden, there was a party and she wasn't there. Steve ended up comforting me and I felt really selfish."

Sometimes she can't believe that her sister has gone.

"I don't know if it's her floating above me watching me, but I definitely feel her spirit."

A seven-year rift between Coleen and two of her sisters, Anne and Denise, over a row between Anne and Ray in which Denise became involved, is slowly mending.

She and Anne have sorted out their differences, while she remains philosophical about her relationship with Denise, she says.

"Denise wrote recently that me and her will never be friends and she's absolutely right. But we will always be sisters. There will always be love there, but we both accept that we will never be best friends, and I think that's all right.

"I only wish Denise the best but we are very different people with different outlooks on life. Just because we are blood relatives doesn't mean we are going to gel. But we can be in the same room now and at family parties.

"I think we've found a good mutual ground," she says. "It's a waste of time it going on for so long with so much animosity."

:: No Regrets by Coleen Nolan is published by Penguin, priced £16.99. Available now