Hi,
I looked into getting stamped in the UK.
You need to apply to the embassy. You have to get the forms from there or call an office (but you can only call from the UK). You then need to complete the forms and deposit the visa cost (about 60 pounds) into a bank using a deposit slip that they give you and you have to do it in England and with English money. You also have to call ahead for an interview. Again calls can only be made from England and you have to call 4 weeks ahead to book an interview. None of this can be done online.
Of course you might get told to call 2 weeks ahead like I did so you go ahead and book your trip. Then they tell you that the day you want is full and try again. They will also insist on taking at least 5 full days to process and they will send the passport back to you in the UK to an address where someone has to be available to sign for it, using a envelope that can only be bought in the UK.
And if all of this and the changes they force you to make doesn’t fit in with your plans that you have already made and you have to cancel your trip with less than 2 weeks notice then they will say it is your fault and will not refund the visa application fee.
A throughly unpleasant and difficult situation which they have no intention of making easier.
I went through all of this and found them nearly impossible to deal with. It cost me money, it meant that I missed out on a few trips for my company and interferred with my job. So a big thank you to the US embassy in London. NOT.
Oh yeah – I am English and this was a renewal of a H1b. It wasn’t anything new or a 3rd party citizen.
I ended up sending my passport to St Louis. 3 months later I am still waiting and I still cannot travel back to England.