mjhjmtu

so why did we hold that vote in the first place?

Mainly for the following two reasons:

For some, to put pressure on the government to ensure that there is either a deal or no Brexit

For others, so they can blame it all on the government even though they know full well they've done nothing to actually prevent it, by saying 'look, we voted against no deal'.

Trying to force though "the deal"

This is the main reason for this vote.

The prime minster is hemmed in and is trying to show that there is no other option but to accept "her deal", as already negotiated with the EU. She knows that there is not a majority for "no deal" in the parliament. So the vote is a way to show to everyone that the majority of parliament do not want a no deal, vis a ve parliament (or more to the point the pro-brexit MPs) should accept her deal. It's trying to prove to the MPs that say "we should leave without a deal" that they are in the minority.

Context

This needs to be viewed in the context of what is currently happening. There are lots of factors at play here, some big ones include (not an exhaustive list or we'd be here all day):

• The current government is a minority government without an overall
  majority in the house, it is only in power currently because of a
  loose arrangement with the DUP. This is so loose that the DUP has
  voted against the government several times! So the government, even
  if it could force ("whip") all of it's MPs to vote with it, still
  cannot make parliament accept the current deal on the table on its
  own.


• The government has lost 2 major votes votes on its main policy
  ("Brexit"). Under normal circumstances this would cause the
  collapse of the government and a general election.


• Earlier last year, the Prime Minister barely scrapped a no
  confidence vote.
  This has again highlighted that the government cannot produce a
  majority. Again, Under normal circumstances this would cause the
  collapse of the government and a general election.


• The government tried increase its majority with its snap election of
  2017. The idea being that if it had a larger majority it could better sideline the more extreme wings of the party (such as the ERG).
  This tactic failed miserably resulting in the Conservative party
  losing its majority. So the Conservative party really doesn't want
  an election because it's afraid it will lose it or it'll make
  matters even worse (again!).


• The DUP could withdraw its support to the government; this would
  cause the collapse of the government and a general election. The
  DUP doesn't want an election though because it now has a lot of
  power. The DUP is a "Northen Ireland Unionist" party. It is usually a small player in wider UK politics but has a strong vested interest (obviously) in the border between northern and southern Ireland.

So at the moment the UK government is basically after something it can call a win in any shape or form, even if it's not binding at least it shows progress.

You can see form above just how tentative the current governments grip on power is. The current state of affairs is totally unprecedented. At any other time this government would have collapsed a long time ago or at the very least the prime minister would have resigned. Why has none of this happened? Because there simply isn't enough time to hold elections, etc. before 29th March.

The government never wanted to have this vote. It's been forced into by the circumstances. But without the government it's hard to make votes legally binding in the current circumstances. So the government is trapped by parliament and parliament is trapped by the government. Eventually (dear god hopefully soon!) one will have to give.

A vote cannot rule out Brexit, legally

The other thing here is that there is primary legislation(an act of parliament) that says the UK will leave the EU on the 29th March.

The only way to revoke this is with more primary legislation. This vote is not primary legislation. Revoking article 50 would require a new Act of Parliament. The EU has said the UK can revoke article 50 whenever it wants, the UK act of parliament says this isn't possible. This was only a vote on the original Brexit bill.

Unless a deal is agreed by the 29th March, then the legal default is no deal, no matter how many votes in parliament say that it's not true, the law says no.

This is old-fashioned power politics of a type rarely seen in the UK, normally associated with times of extreme crisis. Normally Parliament is irrelevant: the Government produces a policy, whips the MPs to vote for it, and it always passes.

Until 2010, there was a strong guarantee that ensured a way forward could always be found: the confidence vote. A vote could be declared a confidence vote so that voting it down would force fresh elections. The effect of that was that government MPs were extremely reluctant to vote against the government on a confidence vote given the high risk of losing their seats. Under this approach, either the deal would be approved or we would be having another election right now.

The Liberal Democrats broke that with the Fixed Term Parliaments Act.

Now the government staggers on, having completely lost control of the process and being reduced to voting against its own motions. And yet May remains as PM, because who else is there? The Conservative Party failed to elect another leader. A no confidence vote was held in January and failed to remove the government. But at the same time there is no majority for doing anything specific. Achieving one will either (a) require the ERG and/or hard Brexit group and/or DUP to surrender (unlikely); (b) require enough of the Opposition to vote with the Government to back the deal (unlikely); (c) require May to give up on her Deal; or (d) require some other option to be assembled and members of the Government to break the whip to vote for it.

The votes are an opportunity for a coalition to assemble. If there's a majority for "not no deal", can that be turned into a deal / delay / rescind majority?

The point of the votes on no deal and on an extension to the leaving date, is for Theresa May to pressure the Democratic Unionist Party (her 'confidence and supply' partners) and the European Research Group (hard Brexit conservatives) to vote for her deal.

Others have addressed the motivations, I'd like to explain how the UK Parliament works.

Normally only the government proposes legally binding votes. It is perfectly possible for other MPs to make legally binding amendments to government bills, but unless the government chooses to back them they are very rarely passed. So more often they are not binding and more of an advisory or statement of the will of parliament, which has a much greater chance of passing in the face of opposition from the government.

Non-binding motions are also much less damaging to the government if they are passed without its support, and MPs of the party of government tend not to want to damage their party for fear of losing power.

On Wednesday we saw a binding motion from Hilary Ben nearly pass, only failing by a mere 2 votes. The situation is precarious and Tory MPs don't want to bring the government down, while opposition MPs want to get their amendments passed by making them as palatable as possible to Tories by being non-binding. Even so, where there is apparent support, binding amendments are being put to the test.