American citizens travelling to the UK for a vacation don't need to get a visa, but will need a valid passport. During your flight, you'll be asked to fill out a landing card where you’ll have to provide your name, date of birth, gender, nationality, occupation and the address where you will be staying in London which must be shown with your passport at the security control.
Australian citizens travelling to Great Britain as tourists for a period of up to six months do not require a visa. If you plan on spending over six months in the country, you will have to pay a £200 per annum Immigration Health Surcharge from the 6th of April 2016 onwards. To enter the country, you will need to show a valid passport. You will also have to fill out a landing card once on the plane providing your name, date of birth, gender, nationality, occupation and the address where you will be staying in London.
EU, EEA and Swiss Citizens
As citizens of the European Union and European Economic Area, you won't need a visa to enter the country. However, depending on your nationality or the duration or purpose of your trip, you may need a visa.
You can check all the necessary information regarding visas by clicking on the link below:
If you have any queries about border control, it's best to contact the British Embassy in your country or consult the information on the website of the UK border control agency:
For more information, visit the official UK foreign office website.