My daughter was so excited when she saw the big pile of post on the doormat when we returned home after a week away. She picked it all up and diligently sorted through it to see if any of it was for her.
It wasn't.
I tried explaining it was all junk mail and bills, but to no avail. She started crying and was soon inconsolable. Her whole body shook as her tears fell. "But why don't I ever get any post for me?" she sobbed. Her younger brother then started crying because he wanted some post too.
So I did what any mother of a heartbroken four-and-a-half-year-old and nearly-three-year-old would do. I tried to make it better. "How about we get you some pen pals?" I suggested. "And then you can have some post of your own."
They were delighted. They know I still write to my pen pal who I met on holiday when I was nine years old – they love popping letters in the post box to her and always ask me what's in her letters.
I remember how magical it felt as a child when a letter would arrive from her with my name on the envelope. How interesting it was to compare schools, friends, Brownie packs.
How I tried my hardest to make sure I wrote to her in my best hand-writing, even looking up how to spell unfamiliar words in the dictionary. Yes, I thought, this is a fantastic thing for my children to do – and if they are that desperate to get post, I'm sure other children will be, too.
I was right. An appeal among my Facebook friends for little ones of a similar age who would like to write to my children, and receive letters from them in return, resulted in lots of positive responses within minutes.
My children were delighted when I told them I had found eight pen pals for them to write to.
One was a little girl they used to go to toddler classes with, but who we don't see very often now they both go to different schools. One was the son of a fellow journalist, who I know professionally even though we have never met in person.
A friend who lives in Canada put me in touch with her friend who has a daughter and son the same age as mine. A girl I haven't seen since we left school said her two would love to receive post.
A former colleague who doesn't have any children asked if they would like to receive letters about her dog's adventures too.
Of course they would, I told her, knowing how amusing they would find getting post from a dog.
The next day, we headed to the shops and bought a pile of postcards with pictures of our hometown of Cardiff on, some writing paper and envelopes, a big book of stamps, and a scrapbook to stick all their post in, and set about writing to their new postal buddies.
My daughter is still learning to write, so it's been great for her to practice words she is familiar with, as well as sounding out unfamiliar ones and working out how to spell them. I point out letters to my son and he likes to draw pictures on the writing paper as his contribution.
Most of their letters are currently dictated for me to write down though, although I am sure that will change as they get older.
I held back from making any suggestions about what they might want to include in their letters, keen to see what they thought was important enough to tell their pen pals.
One of the first letters was mostly about the new lunch boxes they had just bought ahead of starting school and nursery in September.
Another was about the big slide at our local park, and feeding the ducks. I suggested they might like to ask some questions too, to find out what the other boys and girls had been up to. They wanted to know what life was like in Canada, London and Exeter. Whether they have parks in those places was a big concern.
One of the first letters they received was from the little girl they know from toddler music classes. My daughter was in awe at the beautiful unicorn her friend had drawn. She spent all afternoon trying to recreate one herself.
A few days later, we received a letter from Canada, complete with Canadian stamp and international post marks. They were so excited. We bought a children's atlas at our local discount book store, so we could see where it was in the world and what their flag looked like. We talked about what the weather might be like there, and what they ate.
Over the next few days, we received surprise postcards from family and friends holidaying across the world. They had seen my appeal and wanted to join in. We went back to the atlas to learn about France, Bermuda, Scotland and Spain.
It's been a fascinating experience so far – fun, but educational too. We're forever hearing about how the art of letter writing is disappearing so I have enjoyed explaining to my children that they need to write their address at the top of the page, that we start with the word 'Dear', and explaining how postcards are different to letters. I love that they are developing these skills in such a digital age.
And I love that they have developed a sense of empathy and responsibility to the other children too – they keep telling me how excited their new friends will be when they get their post.
Helen, mother of two of our young pen pals, says she has loved exchanging letters so far. "I jumped at the chance as I loved having pen pals when I was a child," she says.
"I loved the excitement of receiving your own post through the letter box and that someone had taken the time to put pen to paper to get in touch. I also thought it was a good way of practising their handwriting. It is so lovely for us to see the effort that is put into the letters we receive, which in turn makes us want to create just as lovely letters when replying."
Louise, the mother of our new Canadian pen pals, agrees. "Almost daily we walk to our mailbox at the post office and without fail my children (four and a half and three years old) ask 'Is there any mail for me?' And I always have to say, 'No, sorry, not today'. So they will be thrilled to finally receive a letter, especially from overseas.
"In this age of instant messaging and FaceTime it's great to think they can establish a new friendship the old-fashioned way."
I couldn't agree more.