Sue Radford shared a sweet picture of her 22nd baby, Heidie.

You’d think that the mum of Britain’s biggest family would have seen it all over the years.

But until now, none of the parent’s children have ever sucked their thumb.

In a picture shared with Sue’s 304,000 Instagram followers, Heidie looks really calm as she dozes with her finger in her mouth.

She captioned the image: “So after 21 babies we finally have a thumb sucker.”

In less than an hour, the post has racked up 5,400 likes and dozens of gushing comments.

The Radfords say baby number 22, Heidie, is the first thumb-sucker of the lot

One fan responded: “Heidie is so precious! Love the picture!

“None of my kids sucked their thumbs.”

Another wrote: “What a cutie. She looks so peaceful.”

A third commented: “The cutest thing ever – all mine did too.”

And a fourth added: “Aww bless her! I used to suck my thumb and my eldest son did too!”

Sue seems smitten with baby Heidie, who was born in April
Sue and Noel Radford are parents of Britain's biggest family

Ever since Heidie was born on April 3, fans have been checking up on her on social media.

Due to the coronavirus pandemic Sue and her husband Noel have faced parenting challenges like she never has before.

After a 10-hour labour, the pair started raising their little one in lockdown.

They’ve done this in their ten-bed home in Morecambe, Lancashire, where they live with 19 of their children.

Some of the Radford's huge household

The kids that live in the house are Chloe, 25; Jack, 22; Daniel, 20; Luke, 19; Millie, 18; Katie, 17; James, 16; Ellie, 15; Aimee, 14; Josh, 12; Max, 11; Tillie, 10; Oscar, eight; Casper, seven; Hallie, five; Phoebe, four; Archie, two, Bonnie, one; and baby Heidie.

Meanwhile, their eldest sprogs Chris, 30, and Sophie 26, have freed up a bit of space at the house as they have flown the nest.