Doctors' leaders aimed to tie the Department of Health "in knots" for up to 18 months in the row over a new contract, leaked messages reveal.
WhatsApp messages between members of the British Medical Association (BMA) junior doctors' committee show heated talks over the best action to take to win the dispute with the Government, and divisions between the junior doctors' arm of the BMA and its top leaders.
Committee chairman Johann Malawana told the committee via WhatsApp in December that the "best solution" might include playing out the dispute for so long that it would "force" the Government "to impose (the contact) against our support".
A deal was eventually agreed with the Government this month although it still has to be put to a ballot of junior doctors across England.
Dr Malawana asked if the committee may want to discuss the issue of Saturday being paid at the normal rate with Government officials.
Ex-committee chairwoman and executive member Kitty Mohan said: "It is the only real red line. It's the thing 99% of juniors told us they were upset about in August."
Arrash Arya Yassaee told Dr Malawana: "Bluntly, no."
Dr Malawana agreed and said: "No combination or scenario in my mind gives us a contract juniors would buy that gives you Saturday as plane (sic) time."
On December 15, Dr Malawana proposed "a strategy that tied the DH up in knots for the next 16-18 months".
In January, as talks were under way with Acas, Dr Malwana told the group not to get "too concerned in the Acas rubbish. We need to play the political game of always looking reasonable".
But he also spoke of his fears over a full strike, with doctors withdrawing emergency care. Such a strike occurred in April.
Although he said its potential was essential for negotiations, he added: "We need to somehow not get to a full walk-out. It's a vanity event for juniors. It's going to blow up in our faces."
In March, executive member Aaron Borbora noted that the BMA was calling for the Government to return to talks: "But we currently have nothing to talk about."
It was only at the end of April, after the full strike, that Dr Malawana asked the group whether the BMA should "put everything back on the table", including Saturday pay.
"Ok so if Hunt is simply not going to back down because he sees this as a chance to make a leadership bid by breaking a trade union, is our current aim of lifting imposition by a full front-on attack the right one?
"Or should we trying something slightly different? Offer to talk about anything he wants as long as imposition is lifted and the end result is a contract that is not discriminatory and unsafe."
Under this month's deal, Saturdays and Sundays will attract premium pay if doctors - the vast majority of whom are expected to - work seven or more weekends a year.
Doctors will receive a percentage of their annual salary for working these weekends - ranging from 3% for working one weekend in seven to up to 10% if they work one weekend in two.
Any night shift on any day which starts at or after 8pm and lasts more than eight hours, and which finishes at or by 10am the following day, will also see an enhanced pay rate of 37% for all hours worked.
The discussion shows a division between the trainees and BMA council chairman Dr Mark Porter, Dr Malawana telling the group: "Mark is Mark. I have spent nearly three months working around Mark so I totally know. But let's play nice for now."
In what he later called a "slip of frustration", he said the process convinced him the BMA "needs a root and branch change to make it actually into an organisation that is much more focused on doctors.
"We suffer from a lack of a clear leadership and a clear vision about what a membership organisation should be about."
A BMA spokeswoman said of the leaks, published by the Health Service Journal: "These conversations go back over six months and reflect the anger and frustration felt by junior doctors across the country due to the Government's refusal to listen to their concerns.
"Private discussions should not be mistaken for the agreed strategy of the BMA junior doctors' committee, which was communicated publicly.
"It is less what was said during the heightened atmosphere of the biggest dispute between junior doctors and the government for 40 years that matters.
"What's important is what was done in order to reach a negotiated agreement and ensure that the long-term interests of patients and the NHS are protected."