Four days of strikes by junior doctors next week will cause "unparalleled levels of disruption", the NHS national medical director has warned.Professor Sir Stephen Powis said he was "very concerned" about the potential severity of the impact on patients, with hospitals facing nearly 100 hours without up to half of their medical workforce.

Four days of strikes by junior doctors next week will cause "unparalleled levels of disruption", the NHS national medical director has warned.Professor Sir Stephen Powis said he was "very concerned" about the potential severity of the impact on patients, with hospitals facing nearly 100 hours without up to half of their medical workforce.