- EU-UK post-Brexit trade deal
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Sausages from Great Britain could soon be banned from entering Northern Ireland.
The problem for bangers – along with burgers and other chilled meats – is a section of the Brexit deal called the Northern Ireland Protocol, which the UK and the EU signed up to.
Why are sausages under threat?
Because of Brexit, Great Britain (England, Scotland and Wales) no longer follows EU rules. However, Northern Ireland does – because it shares a land border with the Republic of Ireland, an EU member.
Sausages come into this because EU food safety rules don't allow chilled meat products to enter its market from non-members – like the UK.
However, a six-month grace period has been in place since January where the rules don't apply.
And, under the terms of the protocol, this runs out at the end of June.
Talks on what happens next, as well as on other aspects of the protocol, will be held between the UK and EU on Wednesday 9 June.
UK Environment Secretary George Eustice told the BBC the EU needed to explain why sausage sales to Northern Ireland should stop.
"They haven't given a satisfactory explanation as to why they think it's a problem," he said.
Why was a Brexit deal for Northern Ireland needed in the first place?
During Brexit negotiations, all sides agreed that protecting the Northern Ireland peace deal (the Good Friday agreement) was an absolute priority.
It meant keeping the land border between the Republic of Ireland (in the EU) and Northern Ireland (in the UK) open and avoiding new infrastructure like cameras and border posts.
That was easy when both Northern Ireland and the Republic were part of the EU. However, a new arrangement was needed after Brexit because the EU requires certain goods to be inspected when they arrive from non-EU countries, while some products aren't allowed to enter at all.
So, the EU and the UK negotiated the Northern Ireland Protocol, which came into force on 1 January 2021.
How does the Northern Ireland Protocol work?
Under the protocol Northern Ireland continues to follow many EU rules. This means lorries can drive across the land border without being inspected.
However, England, Scotland and Wales are no longer following those rules – leading to a new "regulatory" border between GB and Northern Ireland.
That means new checks on goods.
Inspections take place at Northern Ireland ports, and customs documents have to be filled in.
This has prompted criticism that a border has effectively been created in the Irish Sea.
image copyrightGetty Imagesimage captionEU law requires checks on live animalsWhat is being checked?
Some food products arriving in Northern Ireland from Great Britain – such as frozen meat, milk, fish and eggs – have to be monitored to ensure they meet EU standards.
They need to go through a border control post, where paperwork is checked and some physical inspections take place.
The new system got off to a shaky start. The EU said in early February that the control posts were not yet fully operational and some goods were entering Northern Ireland without being properly declared.
image captionUnionists say the protocol damages trade and threatens Northern Ireland's place in the UKWhat about supermarkets?
Separate to the six-month grace period for chilled meats, supermarkets were given a three-month grace period where rules on checking food products (like milk and eggs) were not enforced. This was to give them time to adapt and to ensure supplies were maintained.
However, there was still some disruption at the beginning of the year with certain types of fresh produce missing from shelves.
In March, the UK decided – by itself – to extend the grace period until October. It subsequently announced further unilateral moves, to make the trade in parcels and plants from GB to Northern Ireland easier.
The EU has previously said the UK's decision to extend the grace period breaks international law. And it has launched legal action which could end up with the European Court of Justice imposing substantial fines on the UK.
On a visit to Northern Ireland on 12 March, before the EU legal action was launched, Boris Johnson insisted that the government's move was lawful.
What about security concerns?
Checks were temporarily suspended at the beginning of February, over what were described as "sinister" threats to some border staff checking goods.
Unionists are strongly opposed to the checks because they don't want Northern Ireland to be treated differently to the rest of the UK. One group has written to the Prime Minister to withdraw support for the Good Friday agreement.