If it is pulling to the left on braking then the chances are that one of the RHS callipers is seized.
If it were down to other problems you would likely get symptoms on acceleration and deceleration.
For example, my van did this but it pulled the other way on acceleration and it was down to a track rod end.
Oh, and as you have a worrying problem, the Spelling Police will let you off with a caution for 'breaking' rather than 'braking'.
Evenin' all.