It's not hard to understand why they're so concerned: junior doctors make up 45% of the medical workforce, two thirds of them are members of the BMA union which is organising the strike, and they're planning on walking out of emergency as well as planned care.

Their action is likely to affect every region in England.

Consultants and other senior doctors are being drafted in to provide cover. Lots of planned appointments are set be postponed - it's not yet clear how many.

Junior doctors say they have no choice but to take this action which, they say, is as much about feeling undervalued and overworked as it is about pay.

More than 36,000 junior doctors are set to strike on Monday, Tuesday and Wednesday in England.

Consultants will be brought in to provide some cover, but the NHS is warning of "major disruption and thousands of patients may face postponements to their treatment" due to the strike.

The NHS advice is to dial 999 in an emergency and turn up to hospital appointments unless you are told otherwise.

Other things to note are:

*  Emergency care will continue to be available.

*  People needing critical care, newborn baby care, and trauma care will be prioritised.

*  Anyone needing urgent care should dial 111.

*  GP services will not be directly affected by the strike, so people should keep GP appointments.

*  Some hospital dentists will also be on strike.

What do doctors want?

Junior doctors in England want a pay rise of 35%.

The British Medical Association (BMA) calls it pay restoration after cuts of 26% once inflation is taken into account since 2008.

The 35% rise is needed to make up for the 26% cut, it says.

What impact will the strikes have?

Junior doctors represent around 45% of the medical workforce in England.

They include those just out of university through to doctors with 10 years of experience so the strike action will have a major impact.

About two thirds of the junior doctor workforce are BMA members.

They are walking out of both emergency and planned care as well as general practice where some junior doctors will be working as GP trainees.

It means NHS bosses are drafting in consultants and other senior doctors to cover them in emergency care, such as A&E and intensive care.

This will lead to the postponing of lots of planned treatment, such as knee and hip replacements.

Are the two sides talking?

Junior doctor leaders at the BMA have had meetings with ministers and government officials in recent weeks.

But the government says it will not hold formal pay negotiations unless strikes are paused, and the BMA has declined.

Ministers have made it clear they are not willing to meet the pay demands of junior doctors, but do want to "find a fair settlement".

Instead, the government is concentrating on reaching a deal with the 14 health unions representing NHS staff other than doctors after they suspended their strike action.

Talks were held last week with unions representing everyone from nurses and midwives to ambulance staff and physios.

They have involved discussions about effectively offering staff a bonus for this year on top of a 4.75% pay rise and a more generous increase from April for the 2023-24 year - the government has suggested 3.5%, but unions have made it clear they want more.