Update (2:40 pm ET): Britons are still waiting on the outcome of Wednesday's confrontation between the PM and the 1922 Committee of Tory backbenchers, but judging by the latest development, it's not going well for Theresa May.

Andrea Leadsom, the Tory leader in the Commons and considered a critical member of May's cabinet, has resigned, and it looks like May's decision to add a clause calling for a second referendum was the straw that finally broke her.

It is with great regret and a heavy heart that I have decided to resign from the Government. pic.twitter.com/f2SOXkaqmH — Andrea Leadsom MP (@andrealeadsom) May 22, 2019

Leadsom had been rumored to be on the edge of resigning at many points during the ongoing Brexit saga.

We now wait to see if more senior cabinet ministers, particularly Home Secretary Sajid Javid, follow suit.

Either way, Leadsom's departure increases the likelihood that May will either resign or name a date for her departure on Wednesday.

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Update (12:15 pm ET): A senior No. 10 source has reportedly stepped up to deny reports about the PM's impending resignation.

Yet, cabinet ministers' angst over May's 'New Deal' continues to fester, and a flurry of meetings involving the 1922 Committee of Tory backbenchers, May's chief whip, and various cabinet ministers, are underway in Westminster.

Latest coup summary: Sajid Javid, Jeremy Hunt, David Mundell and Penny Mordaunt all reportedly telling May they can't support her "new" Brexit deal. Indirect way of telling her she has to go (while still being able to say they never told her to go) — Gordon Rayner (@gordonrayner) May 22, 2019

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Even by Brexit standards, the blowback to the fourth iteration of Theresa May's Brexit deal was pretty extreme. Tories hated it, and demanded that May remove a stipulation that Parliament vote on holding a second referendum if an initial vote on the withdrawal deal passes.

The fallout has been extreme. It has been a while since a senior member of May's cabinet resigned, but reports in the British press claim that Andrea Leadsom and Sajid Javid, the Tory leader in the Commons and the Home Secretary, respectively, are planning to resign on Wednesday to protest May's Withdrawal Agreement plan.

Losing the support of her cabinet would likely be the final straw for May. Which is why it's not all that surprising that Sky News is reporting that May is preparing to resign Wednesday night. The reports are unconfirmed, but some in the British press are taking them seriously.

Very senior MP tells me the word from the Cabinet corridor in the HoC is that the PM will resign tonight, Andrea Leadsom is poised to resign to launch a leadership bid, others may also resign & David Lidington will take over as acting PM. Unconfirmed! — Jon Craig (@joncraig) May 22, 2019

Adding to the anticipation, the politics editor at the Daily Mail said that Downing Street has refused to deny the report, saying only that May will make a statement later.

If May leaves, David Lidington, minister of the cabinet office and May's de facto No. 2, would presumably take the reins until a leadership contest has been won. May has some more incentive to bow out willingly, since the 1922 Committee is working on getting enough votes to change party rules about a leadership challenge to allow another no confidence vote in the PM.

The pound moved higher on the rumors, presumably because May's departure could lead to further Brexit delay as it would increase the odds of a general election being held later this year.