When people who don't speak English, including refugees arriving in the UK after fleeing war, they are entitled to receive the support of interpreters when dealing with public sector organisations.
The service provides a lifeline for some of society's most vulnerable people to help them navigate places like hospitals, social services and courts.
But reporter Matthew Hill hears allegations the service is seriously failing those who need it most - with tragic consequences.
Data obtained exclusively by File on 4 has revealed over the past five years at least 80 babies have died or suffered serious brain injuries in NHS maternity units in England, where interpreting and communication problems due to language difficulties, were a contributing factor.
The programme also hears from an alleged victim of serious sexual abuse who says she was unable to give police an accurate account of her ordeal because the interpreter was so poor.
Campaigners claim huge disparities in the levels of qualifications required in public service organisations and poor rates of pay have caused an exodus of qualified interpreters, which they claim is putting some of society's most vulnerable people at risk of harm.

Reporter: Matthew Hill
Producers: Ben Robinson and Surya Elango
Editor: Carl Johnston