Overstayed in the UK 10 years ago, left voluntarily, no exit stamp or record

You should assume the Home Office has your exit dates. By 2014, most outbound routes were covered for API data. This data is retained for 10 years. The question you should be asking is whether or not the decision maker has access to this information.

If your student visa was curtailed at anytime, you should assume you have been marked as having been “removed.” This is because the Home Office runs a program whereby they search for students whose leaves have been curtailed against API data to find students who have not left. Students who leave after their leave by date are deemed to have been removed.

If you properly finished your course, and did not have your leave curtailed, chances are the Home Office still doesn’t “know” about your overstay yet even though they have the data.

However, the ECO may request a search of the outbound travel records to determine the date of your departure. This could be done, for example, if the ECO can’t collaborate travel dates from your passport. Again, records more than five years old are restricted so even if the ECO requested this data, chances are he might not know. Since April 2015, overstayers (leaving after that date) should automatically be tagged as such in the ISA system for all decision makers to see. That system still has limitations.

The chances of a visitor visa after a 2 year overstay in the last 10 years are close to zero. If they find out you lie, the chances will be even less.

To sum up: the Home Office had no systems in place to automatically detect overstays in 2014. The only way they would know is if there has been human intervention at some point (this could be a new application where they manually checked your travel records). Since your outbound record is still in their database, it would be risky to ask for a SAR. This is because, if they were to discover your overstay, your record will be permanently marked. The safest route is waiting until 2024 when your outbound record is deleted and then making a SAR to know what data they hold.

The premise of your question suggests that you are thinking of 'forgetting' to mention the period of overstaying on your Visa Application form. My advice is not to forget.

Be under no illusion, your chance of getting a visa after such a significant period of overstaying in recent years is low. But if you omit that information from your application, your chance of getting a visa in the next decade will be compromised too.

Amongst other reasons, visitor visas are required for those countries whose citizens pose a risk of failing to comply with the conditions of stay. In your case those concerns seem to hold true. If you overstayed before, then maybe you'll do so again.

Exit stamps in passports stopped a long time ago, but whether you have already been identified as an overstayer depends on your method and routing of departing from the UK. Checks are made, so assume they know.

Instead of concealing the fact and risking a lengthy ban, be honest and explain what happened in your visa application. If the "unfortunate circumstances" that necessitated you overstaying for 2 years were genuinely unfortunate and you instead weren't just working illegally to earn some extra money then you might be lucky.

Other answers have written about whether the UK authorities know you overstayed. While valid points have been made, these do not go to the core of the issue.

Always tell the truth on any visa application form. If you are asked whether you ever overstayed, say yes. You will then be given an opportunity to explain the circumstances. In your question, you say "due to unfortunate circumstances". Explain the circumstances.

If you have ever broken immigration rules before, this in itself is not a barrier to getting a new visa. Your application will be assessed on its merits right now. The officers will look at your circumstances right now. If you can demonstrate that you meet the rules now, and that the situation you were in in 2014 does not apply any more, then your current application won't be refused "just to punish you for overstaying before".

On the other hand, if you lie on your application then not only will it be refused; but you will be legally banned for 10 years, and even after that ban period expires, the chances of any officer believing you in future are slim to non-existent.

• We don't punish people for mistakes in the past.
• We do punish people for deliberately lying to officers.

Source: former Immigration Officer

The UK does not check passports on exit (so it's normal you don't have a stamp), but that doesn't mean they don't record exits. However, they started doing so for ferry/tunnel/train departures only in 2015. I believe they had the information for air departures before that, so it may depend how you left the UK.

And since 2014 is a lot less than "10 years ago", if they had the info at the time, they most likely still have it.

Also, they most probably have other means to determine that you were still in the UK past the validity of your visa.

The advice is always the same: DO NOT LIE. The chances you will get caught are high, and the consequences may be a lot worse than your current situation.

I strongly recommend you speak to a UK immigration lawyer.