General rule:
通常情况是：
People who are English won't care
英格兰人不介意
Welsh will care and think you're an idiot
威尔士人会介意并认为你是白痴
Scots will really care, and think you an idiot
苏格兰人真的会介意并认为你是白痴
Roughly 50% of people in Northern Ireland will really, really care and think you're either an idiot or being deliberately provocative
几乎50%的北爱尔兰人真的真的会介意，认为你要么是白痴，要么是故意挑衅
So it's not a great strategy. Use “British” if you have to use only one word. For Northern Ireland, I'd always say “Northern Irish” though this has the potential to annoy some unionists/loyalists. Better to take that risk than to say “British” to nationalists/republicans though.
所以这么说并不合适。如果只能说一个词就说“英国人”。对于北爱尔兰人，我总会叫他们“北爱尔兰人”，虽然这有可能会惹恼某些联合主义者或反对独立的人，但冒这个险也要比对民族独立主义者或共和主义者说“英国人”要好。
I am British, and born in England. If people call me English and referring to me as being born in England, but if they are referring to my nationality, it annoys me. I am British, and have British citizenship. The Queen is the Queen of the United Kingdom, but can, informally, be called the British Queen. People who call her the Queen of England are uneducated, as there has not been an English Queen since the Act of Union in 1707.
我是英国人，出生在英格兰。如果人们叫我“英格兰人”指的是我出生在英格兰可以，但如果指的是我的国籍我就会生气。我是英国人，拥有英国国籍。女王是联合国的女王，在非正式用法中可以被称为“英国女王”。叫她“英格兰女王”的人都没文化，因为自从1707年通过《联合法案》之后就再没有“英格兰女王”了。
The problem stems from a lack of understanding between the differences of the United Kingdom, Great Britain, England, Scotland, Wales, and Northern Ireland. It doesn’t help that we have four separate teams in both Football and Rugby. People aren’t taught the difference at school abroad and maybe they should be.
这个问题源于对“联合王国”、“大不列颠”、“英格兰”、“苏格兰”、“威尔士”和“北爱尔兰”这些名称之间的区别缺乏了解。我们的足球和橄榄球都有4个独立球队也没能帮大家理解。国外的学校不教这些区别，其实可能应该教。

Depends which of the four countries they're from. If you refer to an English person as being from England, then no. However, if they're from Scotland, Wales or Northern Ireland, they will be most definitely annoyed. The name UK is more of a political umbrella term that covers all four countries, but the individual country names represent history and culture. Any citizen can be referred to as from the UK, but to be honest they'd probably prefer being referred to as from England, Scotland, Wales or N. Ireland. If they have an obvious recognisable accent, use one of the four to describe them. If they don't, stay safe and say U.K. or British. They'll probably tell you where they're from, and then you say English, Scottish, Welsh or N. Irish. But never refer to someone who is definitely from Scotland, Wales or N. Ireland as from England, cause you'll come across as ignorant and offend them.
这取决于来自4个国家中的哪一个。如果你说英格兰人来自英格兰，他们不生气。然而如果来自苏格兰、威尔士或北爱尔兰那绝对会生气。“联合王国”这个名字更像是一个政治全称，涵盖了4个国家，但每个国家的名字都代表了各自的历史和文化。你可以对任何人说他来自“英国”。但说实话，他们更喜欢被人说是来自英格兰、苏格兰、威尔士或北爱尔兰。如果他们的口音很容易分辨，那就用这4个国家中的一个来称呼他们。如果口音不明显，为了安全起见，还是说“联合王国”或“英国”吧。他们可能会告诉你他们来自哪里，那你就叫他们“英格兰人”、“苏格兰人”、“威尔士人”或“北爱尔兰人”。但绝对不要把你确定知道来自苏格兰、威尔士或北爱尔兰的人说成是来自英格兰，那样你会被认为很无知，会冒犯到他们。