Don’t assume that because you have a visa you will have a no-questions-asked-entry in and out of the UK.

Before you leave the UK (for a quick trip to Paris, Berlin, Florence, wherever) it is always advisable to always carry your additional documentation (work permit letter, student identification, admission letter, marriage certificates if you are a visa dependant, anything) when you travel in and out of the country. When my husband presents his passport and visa upon entry into the UK, each time, he is asked a variety of questions all aimed at getting answers that will either support the information on the visa or not (I get the same). More often than not, UK customs official are courteous and polite but don’t think they are any less rigorous in their checks. Carrying your supporting documents will help you if there are any additional queries about your status that your passport and visa don’t cover. It is also advisable to keep on hand any phone numbers for local contacts you may be able to vouch for your stay in the UK. This can be your housemate, employer, school, etc.

I say all of this to be thorough, but we haven’t had any real difficulty with our visas.

When you travel back into the UK, you’ll also have to fill out a landing card as a non-EU citizen. This mainly has your travel details as well as your address while you are in the UK. Fill it out completely. I used to think this was an unnecessary paperwork task, but I once witnessed a woman at the UK customs gate in the Paris train station who didn’t have her UK address available and the customs agent was not happy about it. She nearly didn’t let her through.

Again, even with a visa, you still are not carrying a British passport and will need to abide by the rules for non-citizens. You will always need to fill out a landing card (I keep a small stack in my travel wallet, filled out and ready to go!).

As you do when you travel to any new country and are presented at customs: answer all questions truthfully, do not be vague and give the customs agent whatever information they are looking for. This will give you the least stressful experience at customs!

If you plan on flying in and out of the country frequently (for any reason) look into signing up for the Iris eye-scanning system. This system allows people, who meet eligibility requirements (long term visas are eligible), to pass through an automated entry gate (and bypassing the queue for customs). It involves a passport swipe and then an eye scan for identification. I love it, personally, and breeze through the non-EU citizens passport line at Gatwick and Heathrow within a minute, or less.