Image copyright PA Image caption Talks between the British Medical Association and government have broken down

Nearly 3,000 operations have been cancelled as junior doctors in England take part in a second 24-hour strike over pay and conditions.

Check-ups, appointments and tests are also set to be disrupted as a result of the walkout, which began at 08:00 GMT.

Formal talks broke down in January and there is mounting speculation ministers may soon seek to impose a new contract, potentially inflaming the row further.

The key sticking point appears to be payments for working on Saturdays.

Follow our live coverage here.

The BBC understands talks have started taking place within the government after NHS bosses told ministers that if they wanted to see a new contract introduced, they would have to make their move this month to ensure it was in place by the summer.

It raises the possibility of a series of rolling strikes as the dispute threatens to escalate even further.

Media playback is unsupported on your device Media caption Joe Barlow, junior doctor: "New contract is not safe for patients"

'Machismo'

In the latest developments:

The British Medical Association (BMA) wants the whole day to attract an unsociable hours premium, but ministers say the hours between 07:00 and 17:00 should be paid at the basic rate

The BMA proposed accepting half of the 11% basic pay rise offered by the government in return for retaining extra payments for working Saturdays, but the move was rejected

Labour has written to Mr Hunt asking if he personally blocked that offer

The government says change is needed to ensure a genuinely 24/7 NHS

A new poll by Ipsos MORI shows two-thirds of the public support junior doctors - the same as it was ahead of the first strike

Image copyright AFP Image caption Junior doctors are taking part in their second strike in a contract dispute

Image copyright AFP Image caption Junior doctors are on strike, but they are still covering emergency care

There are more than 50,000 junior doctors in England - the term covers those who are fresh out of medical school through to others who have a decade of experience behind them.

Talks between them and the government, hosted by conciliation service Acas, broke down at the end of January and despite some informal discussions behind the scenes, there is thought to be little prospect of them restarting.

BMA junior doctor leader Johann Malawana said the government should not force a contract on doctors and should "put [the] NHS before politics, patients before machismo".

But Health Secretary Jeremy Hunt said the BMA was the "only reason" a solution had not been found.

Want to know more?

Media playback is unsupported on your device Media caption BBC Health correspondent Nick Triggle explains BMA dispute with government

The junior doctors row explained

What patients need to know

How close did both sides get to a deal?

What exactly do junior doctors do?

How does your job compare?

Analysis: Time for the nuclear option?

The walkout comes after doctors took part in strike action on 12 January, which led to 4,000 operations and treatments being cancelled - one in 10 of the total.

During Wednesday's strike, junior doctors are once again providing emergency cover, while consultants are working in hospitals and GPs in the community.

NHS England said just over 40% of junior doctors turned up to work - although it is thought the majority of these would have been those who were working in emergency care.

Dr Anne Rainsberry, of NHS England, said the health service was doing "everything possible to minimise the impact" and 92% of operations would go ahead as normal.

She said staff were "ready to respond to any significant increases in pressure" on hospitals during the strike.

Katherine Murphy, of the Patients Association, urged the two sides to reach a deal.

"A lasting agreement must be found to prevent still further disruption for patients and raise the morale of hard-working junior doctors."

Read more from Nick

Follow Nick on Twitter