At the start of the first lockdown, I got a phone call from our children's placing authority.

'We've had a few phone calls from Sarah*; she's worried that you haven't received any of her letters as she's not had a response.'

'She's right to be concerned,' I replied. 'We've never received anything.'

At this point, our two children, Milo* and Mia* had been living with us for three years, with the adoption order and letterbox contact in place for six months. The children's social worker had refused to allow communication with their birth mother Sarah before the adoption order was finalised. I wrote the letters anyway and tried to pass them over to the social worker, only to have them literally thrown back at me during a meeting.

As soon as the letterbox agreement was in place, I put everything I’d written over the previous few years into one long letter and sent it.

Fast forward another five months. The placing authority phoned us to tell us that the letters from Sarah 'aren't really very suitable' and asked whether we still wanted them. We said yes.

Finally, at the end of August 2020, I received an A4 envelope containing a letter stating that everything Sarah had sent was enclosed.

There was nothing else in the envelope.

The letterbox team told me the letters had definitely been included, and that they must have been lost by the post office – even though they were inside a sealed envelope.

They eventually agreed to send me copies from their file. I cried as I looked through photocopies of handmade birthday and Christmas cards with loving messages on that cheap yellow paper used by councils. I braced myself for the ‘unsuitable’ content. Okay, she'd told them she loved them and signed all the cards with 'mum' or 'mummy'. But what I saw was an expression of a mother's love for children she could not be with. I'd rather have them and choose how and when to share them with my children than not have them at all because of someone else's opinion of what my children should see.

At this point, I abandoned the letterbox system and took matters into my own hands. I knew both birth parents were on social media, so I reached out to them via a new account I made with careful precautions to keep our location and surname private.

Our Post-Adoption Social Worker was horrified - she couldn't believe we'd been so reckless. I understood her reaction, and I accept that some children have birth parents who are a danger to them. What I did won’t be safe or right for everyone. But until support for contact is made fit for purpose, there will always be people who feel so strongly about the importance of maintaining birth family relationships that they do what I did. At the very least, letterbox should only be censored by families themselves, who are best placed to judge the risks.

Unfortunately, we haven't had any contact from the children's birth father. Milo is particularly heartbroken by this, as he wants to know that his dad is safe and thinking about him. But Sarah was thrilled to be in touch. As soon as we started talking, two things were revealed. The first was that Milo

and Mia now had a younger sibling who Sarah had been allowed to keep. This makes contact even more important – we’d like them to know each other as children, not just meet up as adults.

Sarah bakes birthday cakes for them and sends recordings of her family singing Happy Birthday. We get regular updates on how the little one is doing. Milo and Mia know that I am happy to send any questions they might have to Sarah.

Milo isn't interested in talking about it much right now. Still, he understands the door is open and occasionally asks to write a message for her. Mia loves writing letters, so she handwrites messages which I photograph and send to Sarah and share any replies.

Generally, though, the communication is between Sarah and me. Whilst I want to share the successes and joys of our children, I don't want contact to take over my life. I can switch between the separate account I made and my own; only accessing messages when I am in the right headspace. This feels somewhat unfair to Sarah, as I'm aware she doesn't have that option.

Sarah would love more than anything to meet with the children face to face, which I am open to at some point. I want them to have a relationship with their birth mother and sibling. Starting face-to-face contact while the children are still young should demonstrate to them that we are open to them communicating with birth family, which should reduce the risk of them feeling compelled to go behind our back and make poor contact decisions when they are old enough to use social media on their own.

However, I believe direct contact would be confusing for the children at this stage. I want their expectations of contact to not be so wildly out of sync with the reality that it causes even worse issues. Milo and Mia are due to start life story work soon, so I hope this helps them understand where they came from a lot better before we begin planning anything more.

Oh, I almost forgot. The other revelation we discovered when we started talking to Sarah? Those letters ‘lost’ by the Post Office? They’d been mysteriously returned to Sarah.

* Names changed for anonymity

Sophie, adoptive Mum.