Across the world, embassies are considered to be territory of the country who's embassy it is.
Thus diplomatic staff working at their embassy are not working in the host country but in their home country.
Diplomats of an embassy would enter a country using a diplomatic passport issued by their country. A diplomatic passport infers on the bearer immunity from many of the laws of the host country (although diplomats are meant to respect the local laws). For instance the embassy would not pay rates and diplomatic cars frequently flout parking restrictions (with impunity).
Thus diplomats would not need a visa to work in the host country but would need a diplomatic passport.
It depends on what your nationality is.
If you are an EU citizen, or a citizen of Norway or Switzerland, you do not need a work visa.
If you are a citizen of any other country you almost certainly do need a visa.
If one of your parents or grandparents were citizens of the UK, you may be able to get a visa because of that.
An overseas national who is not settled in the United Kingdom, will need a work visa to get a job. There is an exception if you are on a student visa, and then you are able to work part time in the UK.
If you get the UK work visa then the work permit is not given to US so you need a work permit for US.
A work visa
You can establish your own business in the UK if you have the UK work visa.
No need for a visa, as the UK is a participant in the Visa Waiver Program.
if you have a current valid British passport you are recognised as a British citizen, therefore you do not need a visa to work in the UK. You can also get the full information from Visa Simple, that provides bespoke support to their clients and customers.
She would need a UK work visa.
No, a UK visa is only valid for the UK. You need a "Schengen visa" for Switzerland.
Yes because your out of Europe
No UK citizens do not need a visa to go to Singapore just like Singaporeans do not need a visa to enter UK
Yes. A UK visa is not a valid Dubai visa
NO, in most cases you do not need a visa to come to the UK for a short visit
No. Northern Ireland is part of the UK, so the visa will cover it.