A lengthy Brexit debate in the House of Commons on Tuesday evening has voted to back an amendment – known as ‘The Brady Amendment’ –  seeking to replace the Irish backstop with “alternative arrangements” to avoid a hard border in Ireland.

The amendment passed by 317 votes to 301, though as yet it is unclear what these alternative arrangments will be.

British Prime Minister Theresa May has said she “is committed to no borders between the North and South.” However, given that the EU (and also the Irish government) have repeatedly ruled out renegotiating the withdrawal agreement already originally agreed with May’s government (which was rejected by MPs), no one knows how this might be achieved with means that won’t result in a hard border.

What alternative arrangments? That is the million euro question.

The Brady Amendment

The amendment was put forward by Sir Graham Brady, who said if the motion was approved by Parliament as it was, it would give May “enormous firepower” to go back to Brussels and renegotiate the Brexit divorce deal.

She now can do this with a majority backing, but the EU is standing firm, insisting the withdrawal agreement “is not up for renegotiation.”

‘The Brady Amendment’ seeks a redrafting of the plans for the backstop, with the plan also to seek an extension to the transition period – the time where the trade and other matters operate the same as it did prior to the UK leaving the EU – until 2021.

MPs also backed Dame Caroline Spelman’s amendment – to ensure the UK will not leave the EU without a deal (although this is not legally binding, just advisory).

A night of political drama if we ever had one. So now Theresa May has two messages for her EU friends – make significant changes to the backstop and also we really, actually, don’t want to leave with no deal. pic.twitter.com/Qair6mzXZ1

— Simple Politics (@easypoliticsUK) January 29, 2019

What is the Irish backstop? 

As a refresher, the Irish backstop is effectively an insurance policy in UK-EU Brexit negotiations. It’s meant to make sure that the Irish border between Ireland and the UK in Northern Ireland remains open (as it is today) whatever the outcome of the UK and the EU’s future relationship negotiations.

Related: ‘Time is almost up’: Theresa May’s Brexit deal rejected by MPs 

The backstop arrangements were agreed between the UK government and EU in November 2018 as part of the draft withdrawal agreement. The main point is making sure the UK and Ireland don’t return to a hard border, which would threaten the 1998 Belfast Agreement which brought peace to Northern Ireland and removed the need for border checks.

It was put forward in May’s original withdrawal agreement, which was rejected earlier this month.

If a withdrawal agreement isn’t signed before the end of March 2019 and we have a so-called “no deal” Brexit, there won’t be an Irish backstop arrangement.

Speaking in the Commons following the vote, Scottish National Party MP Ian Blackford said that by rejecting the backstop, “the Conservative party has effectively ripped apart the Good Friday Agreement” and “ripped apart a treaty that has secured peace on the island of Ireland.”

May said she aims to return to the House of Commons “as soon as possible” with a revised deal, which will be subject to a “meaningful vote” of MPs.

Reports say that Taoiseach Leo Varadkar would be speaking to May as soon as the voting process ended.