You might never have heard of him, but Phillip Lee, a minister, has just resigned from his job in government in public over what he described as the government's "detrimental" Brexit policy.
The government concession is all the more remarkable because of the strength of opposition to the original amendment from ministers.
The government was putting a combative spin on the concessions Tuesday evening: "The Brexit Secretary has set out three tests that any new amendment has to meet - not undermining the negotiations, not changing the constitutional role of Parliament and Government in negotiating global treaties, and respecting the referendum result", a spokesperson for the Brexit department said in a statement. Part B said that if no deal with the European Union was reached by 30 November 2018, the government would have to come to parliament and explain exactly what would happen next.
He also called for the Government's final proposals to be put to the public in a second referendum.
The government has surrendered; and the implications are huge.
Further votes on EU Withdrawal Bill amendments will take place on Wednesday, with no defeats expected for the government after ministers agreed a compromise wording over post-Brexit plans for a "customs arrangement".
Rosie Duffield then quit after the vote, which saw the House of Commons reject the proposed amendment by 327 votes to 126.
"A vote between bad and worse is not a meaningful vote".
At Prime minister's Questions on Wednesday Mrs May said that Parliament can not be allowed to "overturn the will of the British people" on Brexit. "It is, however, irresponsible to proceed as we are".
A Downing Street source said: "We will get a good Brexit deal that works for everybody in the UK".
"Effectively we are going to reproduce the customs union and the single market and the government will not be able to comply with yesterday's legal obligation unless it does so".
One Tory Leaver said: "We need to know more about what exactly the prime minister has told the rebels".
The Lords amendment number 25, which was voted through by MPs last night, states that the United Kingdom government must not do anything which is incompatible with the Northern Ireland Act 1998.
Mr Corbyn says he understands MPs representing constituencies which voted strongly for Leave or Remain had difficulties on the EEA amendment to the EU (Withdrawal) Bill. "We will have to go away, think about it and come back and make a statement".
She has previously spoken of the threats she faced for challenging the government, and revealed that one colleague would not be voting as they wished this week for fear of reprisals.
Grieve's amendment was in three parts.
Before the vote, she assured lawmakers she would honor her promise and deal with the "concerns raised about the role of parliament in relation to the Brexit process".
However, the compromise is only likely to delay a full-blown showdown on the customs union until trade legislation returns to the Commons in July.
Government sources signalled to the Press Association that ministers were set to back the move.