Ignore the shills and dicks, OP.
Lots of pommies do ok in Murica.
The key thing is employment. If you're serious, you need to do a lot of research on how to get an IT job as a foreign passport holder. The fact that you already speak English fluently and have a good skill set obviously works in your favor.
You should be thinking also about where you would want to live, IT jobs are not equally distributed. And the different parts of the country vary GREATLY in climate, cost of living, political atmosphere, and cultural characteristics. IT areas (CA, TX, NYC) tend to be liberal unfortunately. (But even the most leftarded areas do have lots of cool MAGAs.)
Once you have a targeted area if I were you I would come over and visit for a while as a tourist, and network a lot, there are meetup groups, linkedin and other ways that you can make connections. Don't be too aggressive about job hunting right off, just try to get to know people in your field, be nice and get the lay of the land.
Another possibility is to save up your pounds and take an education program over here in your field. This will naturally lead to job offers and you will have plenty of time to figure out everything while you are studying.
Make a nice resume and have a good work portfolio, etc.
It's definitely possible to do what you are doing, I lived abroad for 20 years and more than once moved to a new country without definite employment, just found it after I went there (you do need a cash cushion saved up to attempt this though).
A good way to make money while job hunting is tutoring, if you are an IT guy you are presumably good enough at math to tutor it, and there is demand for math tutors, you can even work online.