(Picture courtesy MOD).
Prime Minister Theresa May's Brexit plan has been rejected by MPs in the House of Commons by a majority of 230 votes.
The 230-vote margin of defeat was by far the worst suffered by any Government in a meaningful division since at least the First World War.
Labour leader Jeremy Corbyn responded by tabling a motion of no confidence in the Government.
The result means the possibility of Britain crashing out of the EU without a deal seems more and more likely.
But what could a no-deal Brexit mean for defence?
By Forces News Defence Correspondent, James Hirst.
I’ve been saying for months “we’re in unchartered waters”, but those waters just got a lot deeper.
This is not where the government, including the Ministry of Defence (MOD), hoped to be but it doesn’t exactly come as a surprise.
Expected it may be but this is still the biggest step in Brexit since the referendum.
The question is has that step taken us towards remaining in the EU, towards crashing out with no-deal, or just in a small circle?
As the political dust settles, it’s likely that in MOD main building, and others along Whitehall, there will be a lot of people saying ‘we are where we are’, and pausing to take stock of where to go next.
They will want answers quickly, but will have to show patience.
If the step is toward a no-deal Brexit that would mean upheaval.
For defence, the biggest concern would probably be economic because currency turmoil presents a big threat to the defence budget.
Billions of pounds worth of new equipment, like the new F-35 fighter jets, are priced in US Dollars so a fall in the value of the pound could make all that suddenly look a lot more expensive.
Add to that the fact the defence budget, and its growth, depend on the performance of the economy as a whole.
Defence planners won’t jump at the first financial numbers they get, it’s not a short sharp economic shock that concerns them, so much as any longer term change that it might turn into.
However, they would look at the range of projections, and whether they might have to make cuts in future as a result, presenting ministers with options for decisions further down the line.
Like the economic fallout, the real diplomatic consequences would take time to see but Britain’s defence relationships are some of the best placed to withstand the storm.
In fact, there is a good chance that defence would be relied upon by the government, through NATO and bilateral relationships, to help maintain ties that are strained in other areas.
Military operations should largely be unaffected, with the exception of bureaucratic questions about continued British contribution to current EU military missions, most notably the anti-piracy Operation Atalanta.
The political will for continued British contribution has certainly been strong on both sides up to this point.
What this latest Brexit twist really means for defence is what it means for the country as a whole; uncertainty.
That’s never welcome and it will be met with appeals for calm heads and strategic thinking.