My russian wife's first husband is dead and her son is living with his mum and I in the UK, he is 10years old next month but does not know that his father was killed in a traffic accident.

I would like to adopt the boy here in England. Is it possible?

What is the best process?

Not that it matters - but does the boy think you are his birth father?

My russian wife's first husband is dead ...

So I assume you are her second husband? Is the boy a Russian citizen or a British subject?

Contact a solicitor about filing the necessary paperwork.