Hospital doctors in England plan to strike around Christmas in their longest industrial action in the history of Britain's state-run health service, after pay talks broke down on Tuesday.

Junior doctors -- those below consultant level -- have already staged several strikes this year because of deadlock over pay demands sparked by the biggest cost of living crisis in a generation.

The doctors will walk out from December 20 to December 23 and again from January 3 to January 9, their union, the British Medical Association (BMA), said in a statement.

Members voted to strike after negotiators for the UK government's health department failed to put forward "a credible offer to end the pay dispute" following five weeks of discussions, the BMA added.

The union said junior doctors were offered a 3.0-percent rise on average this year, on top of an 8.8-percent increase they were already given earlier this year.

The BMA said the proposal would "still amount to pay cuts for many doctors this year".

Julian Hartley, chief executive of NHS Providers, which represents hospital groups in England, said January's six-day stoppage "will be the longest strike in NHS (National Health Service) history during the busiest and toughest time of the year".

A spokesman for Conservative Prime Minister Rishi Sunak described the planned action as "clearly" disappointing. He said the government's offer had been "fair and reasonable".

"Both the dates before Christmas and, indeed, the dates at the start of January are some of the most challenging times within the NHS, which obviously the junior doctors will be aware of," the spokesman told reporters.

Junior doctors have gone on strike at least six times since March. In September, they walked out along with consultants, the first time the two had gone on strike in England at the same time.

Consultant doctors have since reached a deal in principle with the government.

A host of workers -- from train drivers to lawyers -- have staged industrial action in the UK in recent months as inflation has soared, sending food, housing and other costs spiralling. (AFP)