Londoners are being urged to only call 999 for genuine medical emergencies today as parts of the NHS goes on strike.
Thousands of NHS workers, including nurses, midwives and ambulance staff, will be on strike until 11am today (Monday). The strike is expected to disrupt NHS services, but urgent care is not affected.
The London Ambulance Service has said it will respond to "critically ill" patients but others will be told to wait longer or make their own way to hospital.
Trade unions want a 1% pay rise for all NHS staff, but the government has said the proposal would cost too much.
England's chief nursing officer Jane Cummings told the BBC that "robust plans" had been put in place and patient safety "was a priority".
The Royal College of Midwives, which is taking action for the first time in its history, has said services for women giving birth will be unaffected. Instead, their members are likely to target antenatal and postnatal care.
