Surveying in the UK

I was hoping some one may be able to assist me. I am moving to the UK
in approximately one month and hope to obtain work as a land surveyor.
But in the mean time can anyone tell me if there is a national or
regional coordinate system in place in the UK. I am guessing it would
be possibly managed by ordnance survey. How does one get access to the
values of this network and how the positions are ground marked?