The ‘visitor for pleasure visa’ or the travel visa gives foreign nationals a chance to meet family and relatives, avail medical care and enjoy tourist activities. The US tourist visa or B-2 visa is granted for 3 months to a full tenure of 10 years.
However, when you are looking at the US tourist visa from UK the rules are different. For other foreigners, you might get a 3 month single entry visa or a 10 year multiple entry visa, you have the choice of being in US accordingly. But irrespective of the visa that you have, you cannot stay on for over 6 months at any point. And you are not allowed to take on any employment irrespective of whether it is part time or full-time, because you do not get legal authorization to work.
Though 1 extension is possible, it can only be of another 6 months and you need to show strong ties and an intention to go back to your home country, demonstrating that the extension is temporary. To avail the tourist visa, the US Citizenship and Immigration Service looks at your economic and social ties to the home country, and in case, they feel that you do not portray as strong indication of going back, the visa is denied.
The duration of your stay in US is dependent upon the immigration officer at the entry point who belongs to the Customs and Border Patrol units. The date stamped on the I-94 card is the date of departure and you need to go back by that time.
USA has treaties and trade agreements with numerous nations and UK is one of the prime countries that share the benefits including visa waivers. When you are looking for more information on US tourist visa from UK there is a waiver on the fee, which goes the UK nationals coming to US a chance to be there for a period of 90 days. However, all the British citizens going to US are required to register to the Electronic System for Travel Authorization. While the British nationals that have dual citizenship of US are needed to embark and come back on their US passport when traveling to USA. Thus, there is no requirement for a visa.
For foreigners in UK, working and staying there are required to take the US-travel visa from US consulate. Those British citizens going to on US tourist visa from UK on the Visa Waiver program are only allowed in the US for a period of 3 months and then have to return. Just like any other tourists, they are not allowed to work or stay any longer there.
You can talk with an immigration attorney about the probability of going on US tourist visa from UK. If you do not have the ESTA authorization it is impossible to enter USA even as a British citizen. The immigration lawyer is knowledgeable and updated on the regulations about tourist visas and other immigration issues.