If you ask anyone who works at Gatwick Airport, including the information desk, they'll tell you there's nowhere where you can get something printed there. I'm writing this post to inform the internet that that's not true. If you want to know where the printer is, skip to the end. Otherwise, here's my story.
I normally travel to Egypt without a visa, as I'm able to convince the border control that I was once Egyptian. People of Egyptian origin don't need a visa in theory, although sometimes an officer will insist that you still do, and you need to talk your way out of it. They like to power trip, so you need to be quite friendly and smooth so they can let you through "just this once, but get the visa next time". This can be quite stressful actually, but I'm just too cheap to pay for a visa.
The way I can convince the border control is:
Without that third bit of evidence, my case is quite hard to prove. I also can't just show it on my phone -- having it printed adds to the legitimacy. Not too long ago, I found myself at Gatwick airport going to Egypt, and realised I had forgotten that physical copy. I only had the WhatsApp image my mother had sent me long ago. I needed a printer.
I was early for my flight so I went and asked the information desk, to no avail. They said there's nowhere that could have a printer that travellers could use. I didn't believe them, so I first went and checked the Boots and the WH Smith etc. You never know what store might have a printer and charitable staff, especially a pharmacy. But unfortunately no dice.
Then I thought that the most obvious next place must be the airport lounges; surely they must have a business centre with a printer? I was flying economy, and not about to pay for lounge access, but I thought I'd try asking staff again to just let me in to print one thing and leave. Unfortunately, it seemed like literally none of the lounges had that!
As I was about to give up, I approached the final lounge in the upstairs of the lounge area. I asked the man at the counter if they have printers, and he said that they offer a printing service, for exactly one pound. Music to my ears! I left the queue and emailed him the image, and he printed it right there and then. It was all stretched and cut off, so I asked him to do it again and helped him get the print settings right (he didn't charge me the second time).
With my document in hand, I went back to the info desk and when they saw me approach with that sheet of paper in hand they were in shock! They said so many people ask them this and they always say that there's nowhere to print, so they were very grateful that I could update their information on this. Never give up until you've turned over every stone!
So where is the printer in Gatwick Airport? It's at the counter of Plaza Premium Lounge. I even found a photo online -- it's behind the counter where I put the red rectangle!