Seat belt restraint system

The invention relates to a vehicle occupant restraint system comprising a belt extending from two effective belt guides (4) located on each side of a seat (2) and which when fastened around an occupant (1) has a belt configuration defined by at least two effective side positions (P) where the belt emerges on each side of the seat, wherein said effective belt guides (4) are arranged to be movable upon acceleration of the occupant (1) in relation to the seat (2) in a crash situation so as to accomplish a forward displacement of the effective side positions (P) in relation to the seat (2) for altering the belt configuration from a crash restraint configuration to a ride down configuration.