US Democratic presidential candidate Joe Biden warned the UK that unless it honours the Northern Irish peace agreement, there will be no post-Brexit trade deal with the US.
“We can’t allow the Good Friday Agreement that brought peace to Northern Ireland to become a casualty of Brexit,” said Biden on Twitter.
“Any trade deal between the U.S. and U.K. must be contingent upon respect for the Agreement and preventing the return of a hard border. Period.”
Britain fully leaves the European Union on 31 December 2020. The UK is still in negotiations with the EU over a number of issues from trade, migration, to fishing rights. If the UK does not seal a wide range of agreements with the EU, it will be forced into a no-deal — or hard — Brexit.
Watch: What is a no-deal Brexit and what are the potential consequences?
Sealing trade deals with major economies is high on the agenda for the UK government because it’ll lose all the favourable conditions with its biggest trading partner — the EU — when it stops becoming a member.
But the Northern Ireland aspect of the deal has become a sticking point for agreements.
The fear is that without an agreement with the EU, there could be the creation of a hard border with customs, security and passport control between the UK's Northern Ireland and the Republic of Ireland.
It is deemed as unacceptable as it poses a threat to the balance brought by the 1998 peace process that ended 30 years of conflict between Irish Catholic nationalists and pro-British Protestant unionists.
On 11 September, the UK government announced that it had secured its first post-Brexit trade deal, with Japan.
The UK-Japan comprehensive economic partnership agreement was agreed in principle on a video call between Britain’s international trade secretary Liz Truss and Japan’s foreign minister Motegi Toshimitsu.
The government said in a press release it marked a step towards the UK joining a wider trade bloc in the Asia-Pacific region. The deal agreed with Japan will see tariff-free trade on 99% of UK exports to the country, with officials predicting a £1.5bn ($1.9bn) boost to the UK economy “in the long run.”