从美国去英国旅游，在法律或可能违法方面需要注意什么？

Jonathan Elder Travelled across much of Europe and bits of America and Asia
The UK is pretty free - generally if it’s not disallowed, you can do it.
* Your ‘constitutional rights’ have zero meaning here. Attempting to claim them will get you laughed at. Saying that, you probably have slightly more rights in the UK than the USA, at least in certain areas.
* Drinking age is 18, even for you. You can drink in public, except in areas marked by signs. Drink driving is treated very seriously.
* Drive on the left. You’ll need a full driving licence, car insurance, car tax and have to have a yearly MOT test to make sure your car is safe to drive.
* A lot of roads have automated speed cameras. Some of the motorways use average speed cameras or variable speed cameras. Speeding is not wise - even if you see others doing it - they probably know where the cameras are.
* Don’t drop litter. Most councils will fine you if spotted.
* Border Controls are not as bad as yours, but they have no sense of humour. At all. Just answer the questions.
* Police, even the armed ones, are friendly if you are. Start arsing around and they can become very unfriendly. Just because they don’t have a gun does not mean you can get away with anything.
* Most of the drugs you would expect to be illegal are. Just having a small personal use amount will usually be treated with a warning, but best to avoid it.
* Prostitution is sort of legal, but if you are driving around looking for one, that is illegal.
* The customer is not always right - at least not when they are wrong.
* Harassment or abusive speech because of race or religion, or threatening violence are potentially arrestable offences. Be nice.

【回答】
英国其实挺自由的，通常只要没被禁止的事你都能做。
* 在这儿提“宪法权利”纯属搞笑，说这个只会被人当笑话。不过在某些方面，英国人的权利可能比美国还多点。
* 满18岁就能喝酒，公共场合也能喝，除非立了禁酒标志。酒驾处理起来特别严。
* 靠左行驶。需要正式驾照、车险、缴纳车辆税，每年还要做车检确保安全。
* 很多路段有自动测速摄像头，高速上有些是区间测速或智能限速。别学那些超速的老油条，他们很清楚摄像头在哪儿。
* 别乱扔垃圾，被市政巡查抓到基本要罚款。
* 边境检查没美国那么严，但工作人员绝不开玩笑。老实回答问题就行。
* 警察（包括配枪的）对礼貌的人很友善。要是你胡来，他们会立刻翻脸。别以为警察不配枪就能随便挑衅。
* 你能想到的毒品基本都违法。虽然少量自用可能只给警告，但最好别碰。
* 卖淫在某种程度上是合法的，但你要是开车到处找妓女，那就是违法的。
* “顾客永远是对的”在这儿行不通，尤其当顾客明明有错的时候。
* 因种族或宗教辱骂他人，或者威胁使用暴力，都可能被逮捕。管好嘴巴。

James McGinty Owner at Professional Speaker and Speaker Coach (2003–present)
I once saw an American refuse to hand over a tiny knife to a security person at the airport. The security person was very calm and explained that this type of knife (button operated concealed blade), no matter how small was illegal in the UK. The American protested that it was OK as it was tiny and just a gimmick knife he used it to clean his pipe. 
After a couple of minutes the American lost patience and said something along the lines of “this wouldn’t happen in America”. Within another couple of minutes the police had arrived, the American was arrested, taken into custody, missed his flight, probably spent the weekend in a holding cell, then would have been taken to court on the Monday, where he would have been given a small fine, unless he was stupid enough to continue his protest, in which case he would have been remanded in custody for potentially 2 weeks to 3 months depending on how busy the courts are. 
Basically don’t be an idiot and stand your ground against British laws that you disagree with.

【回答】
我在机场见过一个美国人拒绝把小刀交给安检人员。安检员非常冷静地解释说，这种按钮式隐藏刀刃的刀在英国无论多小都算违禁品。那个美国人争辩说这刀很小没问题，只是他用来清理烟斗的小玩意儿。
过了几分钟，美国人失去耐心，说了句"在美国根本不会发生这种事"。又过了几分钟警察就来了，美国人被逮捕拘留，错过了航班，很可能在拘留所度过了周末，然后周一被送上法庭。正常情况下只会被处以小额罚款，除非他蠢到继续闹——那样的话根据法院排期情况，可能会被还押候审两周到三个月。
总之别犯傻，不要公然对抗你不认同的英国法律。 

Rita Lamy Retired RN BSN Psych & Mental Health older than dirt
I am an American who has been living here in England for 5 years. Bring NOTHING with you that even looks like a weapon. NO GUN, KNIFE, NAILFILE Don’t be loud. Do not think you are better than everyone else, because you aren’t. Come here with an open mind, enjoy our culture, our accents, our Britishness. Do recognize that a “Full English” breakfast does include eggs, beans, sausage, bacon, black pudding, half a grilled tomato, toast, and hash browns. I absolutely love it here and will never return to the USA.

【回答】
我在英国住了五年。别带任何像武器的东西：枪、刀、指甲锉都不行。别大声嚷嚷。别觉得自己高人一等，因为你并没有。带着开放的心态来，享受我们的文化、口音和英伦风情。要知道，"全套英式早餐"确实包括鸡蛋、豆子、香肠、培根、黑布丁、半个烤番茄、吐司和薯饼。我超爱这里，再也不会回美国了。

David Hawley Series Chief Marshal at MotoAmerica (2015–present)
Very few Americans fall foul of the law, because most Americans are nice law abiding people, and despite some of the hotheads who occasionally go in for hectoring and provoking statements on Quora (usually on the fine details of what “free” really means) there really isn’t any issue. 
Some of those that do get into trouble would have got into similar trouble back home, e.g. for bad driving, getting drunk and belligerent etc. and of course these things aren’t confined to Americans. 
Things that have caught my American wife out when in the UK are minor:
* Her cellphone either didn’t work or the international charges were punitive. For many years I found it was actually cheaper to purchase a basic phone in the UK and use pay-as-you-go services. You can still do this, though I have a better plan now.
* In London the famous taxis are very expensive. Public transport is really good, and an Oyster card, is a good investment, but the tariffs are confusing.
* All prices include tax, where, appropriate.
* Don’t assume that people have any interest in what is going on in the USA or are well informed about it.
* The rest of the UK is not like London, and most people outside London don’t really have any interest in things that are local to London. Even the dear old BBC seems to find that concept hard to grasp.
* If you hire(rent) a car make sure that you clearly specify that you want an automatic. The UK default is a stick shift and if you don’t say that you don’t want a stick shift then you will probably get one. Be aware that a lot of models will automatically kill the engine at traffic stops. This is normal behavior to save fuel . It will start automatically.
* Police are friendly and are usually happy to give directions, and a little local advice.
* The UK has an island climate. Although much nonsense is said about the weather in Britain, all of the UK is north of the lower 48 states and you are never more than about 70 miles from the sea. Although it is never as hot nor as cold as many parts of the USA , the weather can change rapidly, and is notoriously unpredictable.
I assume that you’re not silly enough to think about bringing some kind of weapon to the UK.

【回答】
大多数美国人不会在英国惹上法律麻烦，因为他们都是遵纪守法的好人。虽然Quora上偶尔会有些激进分子发表挑衅言论（通常纠结于“自由”二字的精确定义），但这根本不算什么问题。
那些真惹上麻烦的美国人，就算在自己国家也容易出类似状况——比如危险驾驶、酒后闹事等等，当然这些行为并非美国人专属。
我美国太太在英国遇到的小麻烦倒是值得一提：
* 她的手机要么没信号，要么国际漫游费贵得离谱。多年来我发现，在英国买部简易手机用预付费服务反而更划算。现在虽然有了更优惠的套餐，但这个法子仍然可行。
* 伦敦著名的出租车非常昂贵。公共交通很发达，买张牡蛎卡很划算，但计费规则确实复杂。
* 所有标价都已含税（若适用）。
* 别指望英国人对美国时事有多关心或多了解。
* 英国其他地区和伦敦截然不同，伦敦以外的人对首都本地事务基本不感兴趣。连老牌的BBC似乎都难以理解这点。
* 租车时务必明确要求自动挡。英国默认提供手动挡，若不特意说明就会拿到手动挡车。注意很多车型遇红灯会自动熄火，这是正常的节油设计，车子会自动重启。
* 英国警察很友善，通常乐意指路并给予当地实用建议。
* 英国属海岛气候。虽然关于英国天气的传言很多，但全境都比美国本土48州更靠北，距离海岸线最远不超过70英里。这里既没有美国部分地区那么炎热，也没有那么寒冷，但天气瞬息万变，出了名的难以预测。
想必你不会蠢到考虑带什么武器来英国吧。

Ray Forster Lives in The United Kingdom (1968–present)
It can sometimes rain in sumner, when it doesn't look like it will. 
We (usually, most Brits) have milk and sugar in our tea. Not lemon. 
Bonfire night/Guy Fawkes night is only a British thing. 
Chips are not fries, they are chips. Crisps are not chips, they are crisps. Beans on toast is still a thing to some people. A ‘full English’ breakfast is nothing like you've had back in America. 
Ya’all like to drive over there. We'll walk to the shop, or nip to the shop. If someone says its only a 5 or 10 minute walk, don't believe them! 
Our chocolate is superb. 
Our cheeses are (arguably) the best. Sublime! 
It's football. Not soccer! The clue is in the name (it's predominantly played with the feet). 
In nearly all UK pubs (bars) that serve food, you have to order it from the bar. Don't just sit down for 40 minutes, before wondering why you are not being asked for your order/s. 

【回答】
夏天有时候会突然下雨，明明看着不像要下雨的样子。
我们英国人喝茶习惯加牛奶和糖，不加柠檬。
篝火之夜/盖伊·福克斯之夜是英国独有的节日。
薯条就是粗薯条，不是美式细薯。薯片就是薄脆零食，不叫薯条。有些人现在还吃吐司配焗豆。英式全套早餐和你们在美国吃的完全不是一回事。
你们那边喜欢开车，我们习惯走路去商店，或者"溜达着去买东西"。要是有人说"就走五六分钟"，千万别信！
我们的巧克力特别棒。
我们的奶酪可以说是全世界最好吃的，绝了！
这叫足球，不叫英式足球！看名字就知道（主要用脚踢的）。
在英国几乎所有供应食物的酒馆，都得自己去吧台点餐。别干坐40分钟还纳闷怎么没人来问你要点什么。

James Huffington Former Telephone Interviewer (2019–2024)
Whilst all the other answers are superb for providing details. 
Most of the legal things can be reduced to a single statement. Don’t be a douche. 
Driving - We drive on the Left. You on the right. Drive on the right and you’ll be a douche and crash. 
Guns - Waving a gun around is very douchy, people are just going about their business and you’re there waving a deadly weapon around. 
Healthcare - If you get hurt or see another person hurt, call 999 to get an ambulance. Its completely free. Bleeding everywhere or letting someone else bleed everywhere is very douchy. 
Trash - Find a bin and put it in there. Somebody might have to pick that up and get rid of it eventually. Leaving it for others to do is kinda douchy. 
Conversation - Politics, Trump, Brexit, Religion, Sexuality and Gender are not suitable topics of conversation. Additionally (seeing as you’re American,) speaking REALLY LOUDLY IS REALLY DOUCHY. 
Entitlements - As soon as you cross the border you’re in the UK, your American ‘rights’ mean absolutely nothing here. (Thankfully we’ll lend you our ones for the duration of your stay, trying to bring your own with you is pretty douchy.) 
UK, Great Britain, England, Scotland, Wales, Northern Ireland, Ireland, Republic of Ireland. - These are different things and the differences are subtle, difficult and hard to distinguish but for your own sake try and learn them. I truly pity you if you attempt to call a Glaswegian an Englishman. 
Don’t be a douche, if you are accidentally a douche apologise. (Basic courtesy.) 
Have fun, see lots of things and don’t be afraid to ask questions.

【回答】
虽然其他回答都提供了详细说明
但大多数法律问题其实可以归结为一句话：别当傻缺
开车：我们靠左行驶，你们靠右。要是靠右开车，你就是个傻缺还会出车祸
枪支：挥舞枪支非常傻缺，大家都在忙自己的事，就你在那挥舞致命武器
医疗：如果受伤或看到别人受伤，请拨打999叫救护车。完全免费。血流得到处都是或任由别人流血是非常傻缺的。
垃圾：找个垃圾桶扔进去。总得有人收拾清理。留给别人处理有点傻缺。
交谈：政治、特朗普、英国脱欧、宗教、性取向和性别都不是合适的聊天话题。另外（既然你是美国人）说话特别大声真的特别傻缺。
权利：越过边境来到英国，你的美国"权利"在这里毫无意义（好在我们会借你我们的权利用用，非要把自己的权利带过来就挺傻缺的）
英国、大不列颠、英格兰、苏格兰、威尔士、北爱尔兰、爱尔兰、爱尔兰共和国：这些都是不同的概念，区别很微妙复杂难以分辨，但为了你自己好请尽量搞清楚。要是把格拉斯哥人叫成英格兰人，我真替你捏把汗。
别当傻缺，不小心犯了傻要道歉（基本礼貌）
玩得开心，多看看，有问题尽管问。

Jeff Dray Lives in England (1958–present)
Don't bring any weaponry. 
Yelling “ God damnit! I'm an American citizen!” Won't help you one bit. 
American laws don't apply here and we don't accept US dollars. 
There is no such thing as jaywalking 
There is a lot more to Britain than London. 
Our accents aren't confusing, you just need to listen more carefully. 
Shoes sizes are different, don't scream at the assistant that you're a 10, here you're a 9 
Don't assume that you are superior, British humour will cut you down to size 
Don't “correct” us when we say aluminium. 
This may seem random but I've observed all of these behaviours here.

【回答】
别带任何武器。
喊“操！我是美国公民！”对你一点用都没有。
美国法律在这儿不适用，我们也不收美元。
英国根本没有乱穿马路这回事。
英国可不只有伦敦。
我们的口音不复杂，你只要仔细听就行。
鞋码不一样，别对着店员嚷嚷你是10码，在这儿你穿9码。
别觉得自己高人一等，英式幽默会分分钟教你做人。
我们说“铝(aluminium)”的时候别来“纠正”我们。
这些看起来可能有点随意，但以上行为我在这儿可都见识过。

Tony Bartlett Living in Kent in the UK.
1. The Fifth Amendment doesnt apply in the UK. You will be expected to provide a reason for your actions or go no comment. If you make up an alibi before you fet to court the judge can discount it 
Also the 2nd doesnt app,y. Bring a firearm into the UK without the proper paperwork and it will be taken and you will get a free stay at one of HM no star hotels 
In fact no US laws applying the UK 
Dollars are not accepted. Most shops don't take Euros and France is only 22 miles away. Get a Mastercard or visa. Widely accepted and you get the best rate on the day 
Don't push religion. We are a secular society. If you need to say grace do so quietly 
Turn down the volume. Even those of us with hearing defects can hear you

【回答】
英国不适用美国宪法第五修正案。你必须对自己的行为作出解释，否则就保持沉默。如果在出庭前编造不在场证明，法官可能不予采信。
第二修正案同样不适用。没有正规文件就把枪械带进英国？枪直接没收，还能免费入住女王陛下的"无星级酒店"。
说真的，美国法律在英国统统无效。
这里不收美元。大部分商店连欧元都不收，尽管法国离我们只有22英里。最好办张万事达或维萨卡，到处都能用，还能享受当日最优汇率。
别传教。我们这是世俗社会。要做饭前祷告请小声点。
嗓门小点。我们这儿耳背的人都能听见你们嚷嚷。