As with so many things in life, getting stopped at Passport Control was something I had assumed happened to other people. Somehow or other, owning a British passport had lulled me into a perhaps misguided sense of security and I imagined that the worst I could expect might be an infuriatingly long, post-Brexit queue when arriving or departing.
All this changed a few weeks ago, when my nine-year old daughter Georgie and I were returning from what had been a dream-come-true trip to Disneyland Paris.
Within a few hours Georgie went from spellbound at the sight of Mickey Mouse to sobbing silently at Gare du Nord station - and all thanks to a little-known rule which it's all too easy to fall foul of. I share my experience in order that other parents might be forewarned and, therefore, forearmed.
On handing over our passports at the UK Border Force control booths before boarding the Eurostar, the officer looked us up and down before demanding "And what is your relationship to each other?"
"I'm her mother," I replied, slightly affronted.
"And what proof do you have of this?" she snapped.
"None," I replied. "Nobody has ever asked me for any."
At this point I should explain that, though my daughter's father and I have been together for 19 years, we are not married, and we chose to give our daughter her father's surname.
"Do you have your daughter's birth certificate?" came the next question.
I shook my head. "Not with me."
"You need documentation," the Border Force Officer continued. "Have you heard of child trafficking?"
"Yes," I replied, anxious and beginning to bristle at her tone.
"Section 55 of the Borders, Citizenship and Immigration Act 2009 is intended to prevent child trafficking. And I need you to show me proof of your relationship."
I repeated that I didn't have any proof and the conversation proceeded to go round in circles. Meanwhile Georgie, sensing the escalating stress of the situation, began to cry. That was when the Border Force officer explained that I should see how "my behaviour" had caused this.
By this time I was almost shaking with anger, not only at being unable to protect my daughter, but at the prospect of being prevented from returning home, too.
Eventually, it transpired that a photo of my partner's passport would be sufficient to prove his relationship to our daughter - which he duly texted to me - and finally the Border Force officer let us pass.
We made it onto the train less than two minutes before it rolled out of the station, still both feeling a little sick.
What you need to know
So what is Section 55?
According to Gov.uk, "Section 55 of the Borders, Citizenship and Immigration Act 2009 … requires the UK Visas and Immigration to make arrangements to safeguard and promote the welfare of children in discharging its immigration, nationality and general customs functions." Well that's clear and specific then.
After asking the Home Office Press Office for more information, they referred me to a leaflet titled "Children Travelling to the UK" which apparently Border Force Officers "may" hand out to passengers. The leaflet explains that the Border Force also "work to protect vulnerable children and those who may potentially be trafficked". This is, of course, a necessary safeguard which serves an important function - but that doesn't mean innocent travellers can't also find themselves ensnared by it.
Who needs to be aware of Section 55?
Anyone who is travelling with a child under 18, but has a different surname to the child, can potentially be stopped at the UK Border and asked to provide proof of their relationship.
This includes more people than you might think.
According to a 2022 House of Commons Paper ("Common Law Marriage and Cohabitation"), the number of couples choosing to cohabit rather than getting married has risen by 144% over the last few years - from around 1.5 million in 1996 to around 3.6 million in 2021.
There are also obviously a whole host of other reasons why a parent or relative may have a different name to their children, from divorce and blended families to women who get married but choose not to change their surnames. Not to mention people in civil partnerships.
What documentation should you carry to avoid being detained?
The government website states that you may be required to provide copies of: "A birth or adoption certificate showing your relationship with the child, divorce or marriage certificates if you are the parent but have a different surname to the child or a letter from the child's parent/s giving you authority to travel with the child."
Where can I find Home Office Guidance on Section 55?
A publication on The Home Office Press Office's website titled "Guide to Faster Travel Through the UK Border" contains a single paragraph on "Advice for families travelling with children", stating that if you are travelling with a child who has a different name you may be asked to provide proof of your relationship. "Section 55" does not appear under any searches within the site, so unless you know exactly where to look, this information is almost impossible to find.
So why is it not more widely publicised?
I telephoned the Home Office Press Office to try and find out but the Press Officer I spoke to told me Section 55 was not something he was familiar with. I explained that this was precisely my point.
When I asked the Press Office for a comment, they repeated that information about Section 55 was available on the government's website.
It is, but unless you're travelling to a country with specific visa or vaccination requirements, how many of us feel the need - or have the time - to randomly check for any unknown rules or regulations? I certainly don't. There is also, according to the Press Office, no current plan to publicise Section 55 more widely. My advice? Go armed with all the relevant documentation, and save yourself an unpleasant experience.