Hospital doctors in England have initiated their lengthiest strike action starting Wednesday, raising concerns among health authorities about the added strain on services during the busiest time of the year.

Junior doctors, those below the consultant level, have joined picket lines from 0700 GMT until the same time on Saturday, marking a significant escalation in their prolonged pay dispute.

An additional six days of industrial action are scheduled from January 3.

ALSO READ: Yul Edochie sends strict warning to those who insult president Tinubu

This strike occurs at a critical period for the National Health Service (NHS), grappling with heightened demands due to seasonal respiratory illnesses.

UK Prime Minister Rishi Sunak and hospital leaders have criticized the strike, referring to it as their “worst fears realized.”

Sunak urged junior doctors to reconsider the impact of striking during this challenging time and encouraged a return to negotiations.

The British Medical Association announced the strike after failed talks with the government earlier this month.

Despite an offer of a 3.0-percent increase on top of the average 8.8-percent raise given earlier this year, the junior doctors rejected the proposal, citing uneven distribution across different grades and potential pay cuts for many doctors.

ALSO READ: Ex Bank of England Gov. Set to Lead Bloomberg Board

Health policy is devolved, with administrations in Scotland, Wales, and Northern Ireland overseeing their respective matters.

Junior doctors in Wales are set to walk out for 72 hours from January 15, while those in Northern Ireland are undergoing a ballot for potential strike action.

In Scotland, an agreement has been reached between their counterparts and the government in Edinburgh.

With the NHS traditionally experiencing a surge in hospital admissions in the weeks following Christmas, the strike is expected to cause significant disruption.

ALSO READ: FG set to unveil universal health coverage initiative

NHS England’s national medical director, Stephen Powis, warned of the strike’s potential to create “huge disruption” and place the NHS at a disadvantage during its most challenging period of the year.

The healthcare service is already grappling with substantial backlogs in waiting times, attributed to the postponement of treatment during the COVID-19 pandemic and years of underfunding.