Is this chair an original Adrian Pearsall?  

I don't think so but you can look for it in the extensive Pearsall trade catalogs here:

https://web.archive.org/web/20130810102843/http://www.adrianpearsall.com...

The way the upholstery was done on the arms looks like better technique than on Pearsall furniture, plus the proportions look more balanced. I've reupholstered quite a few Pearsall chairs and the frames are not well made at all, but people are drawn to that very obvious mid-century look and demand for them has shot up in recent years. Chances are pretty good that whatever you have there is much better than a Pearsall. (And "original Pearsall" is a bit of a contradiction. It's true that Pearsall produced a lot of furniture with the company name on it but an awful lot of the pieces are very close copies of American and Scandinavian designers' work.)

Thanks for your response. I also have this chair. The base looks exactly like Adrian Pearsall but the seat is a bit different. It has a design that I have not seen before so not sure if it's original or a copy. I've attached a few pics.

Could you post a photo of or link to a verified Pearsall chair with a base that "looks exactly like" this one?