Thousands of British junior doctors have taken to the streets in London to protest against new contracts imposed by the government.
Officials from the National Health Service (NHS) and social activists were also among the demonstrators.
Under the current proposals, trainees would lose pay boosts they receive for working evenings and Saturdays, which will be treated as regular hours.
The protesters say the proposed pay cuts and longer hours will result in junior doctors making more mistakes while they care for patients.
The British Medical Association says the new contract is both unsafe and unfair, however, the British government insists on imposing it regardless of protests.
The demonstration comes ahead of a 24-hour walkout due to begin on Wednesday, when junior doctors across the country will only provide emergency care.
It was the third time junior doctors have protested against the government's proposals, which it says aim to improve care over weekends.
Talks between the Department of Health the British Medical Association doctors' trade union have reached an impasse over weekend pay rates.
The news comes as the NHS is already facing an almost £1 billion deficit, the worst financial position in a generation.