A heartbroken family have paid tribute to a "perfect" three-year-old girl and her unborn baby brother who died after an eight-vehicle pile-up on a dual carriageway.
Little Isla Wiggin was injured along with her pregnant 31-year-old mother in the collision, on the northbound carriageway of the A34 at Hinksey Hill, Oxford, on August 25.
She was taken to the John Radcliffe Hospital but later died.
In a statement released through Thames Valley Police the family said they were "extremely proud" to find out they were going to have a son "who would have completed our family". They had called him Harry because Isla said that was the name she would like for a boy.
They said: "Isla was as perfect a daughter as you could ever wish for. Beautiful and witty, yet cheeky and mischievous, she was a character that you couldn't help but love with all your heart.
"Isla put her heart and soul into everything and all of her friends were 'best friends' who she adored.
"She and her mummy were like two peas in a pod who did everything together, she even loved to help out around the house.
"Her loving and caring nature would have made her an amazing big sister and she was so excited at the prospect. Although adamant that the baby was a girl, Isla said she'd like to call the baby Harry if it was a boy, so it seemed only right to do so.
"We were extremely proud to find out that we were going to have a son, who would have completed our family. He had big hands and strong arms and no doubt would've grown into a strapping young man who would have loved and protected Isla. We are so sorry that we didn't get the chance to meet him properly and get to know him.
"We are very grateful for all of the love and support we have received over the last week. Although nothing can ever make up for the heartache that we feel, it is comforting to know that our beautiful children never witnessed any evil in the world.
"Not a day will go by where we won't think of them and all the happy memories that we have shared."
The collision involved a heavy goods vehicle and seven cars.