One of Scotland's biggest families is about to get even bigger - with the expected arrival of their first grandchild.

Dundee couple Emma and Roy Hann, who have 13 children together, are set to welcome the new baby in August after their daughter Polly announced she and husband Michael Watt were expecting.

"We were kind of expecting someone to be announcing a pregnancy at some point," says Emma.

"We were kind of suspicious that Polly and Michael would be the first to have children."

The 47-year-old 'supermum' and husband Roy, 48, are proud parents to Rachel, 25, Sophia, 24, Polly, 22, Charlotte, 21, Alice, 18, Annabelle, 16, Jennifer, 14, Isabella, 13, Jonas,11, Enos, nine, Eva, seven, Posy, five, and Meg, two.

Eight of the family still live at home and they get through 50 pints of milk, 21 loaves of bread and five large cereal boxes a week.

Their large washing machine is rarely turned off and dinners often consist of huge homemade meals whipped up by Roy before he heads off to local hospital Ninewells, where he works as a nurse practitioner.

Daughters Rachel and Polly are married and the majority of the older girls have moved out with just eight Hann children living in the family home in Dundee.

Emma says the converted semi-detached house feels smaller these days, but their children often pop in and out to visit.

The close knit family are overjoyed with the news that the brood is expanding, with the children delighted at the prospect of becoming aunts and uncles - the youngest of which will be just two when the baby arrives.

"They've been brilliant," Emma says. "Annabelle is 16, and she has made up a little dresser drawer with some clothes and nappies, getting some stuff together.

"Annabelle has used some of her pocket money to help with it. It's really nice."

Emma and Roy's children often show generosity towards each other, with the older children taking the younger ones on trips out, baking cakes for one another's birthdays and clubbing together to buy their parents Christmas presents.

Now the family have backed the new Race for Life Family 5k, a first for Cancer Research UK which sees men allowed to take part for the first time.

Emma explains: "My girls have quite often done the Race for Life and we as a family have quite often gone up and cheered them on and we've all really enjoyed going being part of that.

"So to help with the fundraising side of it all, we were quite excited to be helping with that."

Emma plans to walk the course and Roy, who regularly works with cancer patients through his job, will also take part at Dundee's Camperdown Park on June 18, which falls on Father's Day.

"So often in my job as a nurse practitioner I try to help patients who have cancer. I've seen first-hand how devastating the disease can be," explains Roy.

"That's why I'm determined to do everything I can to help fund research to help beat cancer sooner."

The charity is important to the Hanns - Roy's brother Ben went through thyroid cancer while Emma's brother-in-law Paul was successfully treated for testicular cancer.

"Roy says he's going to put Meg on his shoulders so he might be walking it as well," Emma laughs.

Until then, the family are looking forward to expanding their brood with their first grandchild.

Roy said: "I love being a dad and I'm really looking forward to becoming a grandad.

"I'm so proud of all 13 of my children. I love watching my children grow up. I like just to be there to help them, to play games with them and see how they're learning and changing.

"As busy and as difficult as family life can sometimes be, it makes me happy."

Emma adds: "It's really exciting, I can't wait to be able to do stuff with Polly as a new mum and to be able to have our little grandbaby - she's going to have lots of helpers for babysitting and a lot of people to love it!"

Sign up for Race for Life at raceforlife.org or call 0300 123 0770.