If boris johnson hoped that unpicking his brexit treaty would appease pro-british unionists in northern ireland who oppose the uks divorce deal with brussels, he is wrong.

Were still angry, said sammy wilson, brexit spokesman for the democratic unionists, who were left feeling abandoned by the prime minister when he signed the withdrawal agreement with the eu last year the treaty which paved the way for the uks exit from the bloc in january.

Were even more angry that a lot of the other things which we have pointed out in the deal which are detrimental to northern ireland have not yet been dealt with.

Mr johnsons introduction of new legislation earlier this month that threatens to tear up key elements of the withdrawal agreements northern ireland protocol has pulled the region back into the centre of the brexit row.

For the unionists it does not go far enough. for the nationalists who want the region to join the irish republic, it stokes fears about a creeping return of border checks. business leaders, meanwhile, argue it makes an already complicated situation worse.

The european commission has threatened legal action if the uk does not rewrite the bill to preserve the treaty, but the commissions president ursula von der leyen has said she is convinced a trade deal with britain is still possible. both sides are racing to clinch an agreement before the uks brexit transition period ends on december 31.

It comes at a sensitive time for the region, which, like the rest of the uk and ireland, is grappling with resurgent coronavirus infections and worsening economic fallout from the pandemic.

After years of wrangling over theresa mays irish backstop, the protocol was designed to keep open the 310-mile border with the irish republic and thus protect the 1998 good friday peace pact, which settled three decades of violence in northern ireland.

But mr johnsons move to override key parts of the deal notably on subsidies for ni companies and on customs arrangements has prompted concern that the irish republic would have to carry out checks on cross-border trade to comply with eu internal market rules if the trade talks failed. this in turn has fuelled accusations from nationalists that mr johnsons move will damage the 1998 deal.

Any u-turn by boris johnson would be an extraordinary and indefensible act of bad faith which would totally undermine his credibility and that of the british government, said mary lou mcdonald, leader of irish nationalist party sinn fin, in a statement responding to the uk prime ministers bill.

Only nine months have passed since the dup and sinn fin ended a long political dispute to restore their power-sharing regional government after three years of deadlock. they remain diametrically opposed on brexit which the dup supports and sinn fin opposes and struggled for months to find a common voice on responding to the coronavirus.

Any failure to strike a trade deal would pile yet more pressure on the regions ailing economy, said glyn roberts, chief of retail ni, an industry group that represents 1,800 independent retailers and wholesalers. the prospect of the huge economic downturn thats coming with covid and a no-deal...for any responsible government or politician would be absolutely a nightmare scenario, given whats at stake.

With business still in the dark about many post-transition trade arrangements, mr roberts said reworking the treaty didnt help achieve clarity. it certainly complicated an already complicated situation.

Mr roberts said he had recently spoken with northern ireland secretary brandon lewis, who was the first uk government figure to acknowledge the breach of international law last week. i made that point directly that we have to have this generosity of spirit [to advance the trade talks] and politicians need to be careful with language because the economy is in a bad way, he added.

The northern ireland protocol is a source of deep rancour for the likes of mr wilson, an ardent brexiter who wants northern ireland out of the eu on the exact same terms as other parts of the uk and fears compliance with the new regime will be too costly for business.

The government is now admitting all the things which they denied when the withdrawal agreement was discussed in the house of commons around the end of last year when we made it quite clear that [it] allowed for the eu to continue to have a foot in the decision-making door of the uk as a whole and northern ireland in particular, he said.

But mr wilson dismissed the prime ministers legislative move as tinkering with the treaty, noting that changes apply only in a no-deal scenario, and arguing that he should have gone further.

Yes we are still bruised, he told the financial times in an interview near belfast port, where he expects border posts to be built despite mr johnsons promises that there will be no new infrastructure after brexit. do we trust the government to deliver on all of this? no. i dont think you can, given their past record.

But mr johnsons move on the treaty has also raised trust questions on the other side of the regions historic schism.

Conor houston, a business consultant who works with local and international firms, noted that brexit had already increased pressure from sinn fin and other nationalists who want a referendum under good friday agreement provisions to bring northern ireland into the republic.

Although mr houston believes the time is not right for such a poll, he said uk moves to pull back from an international treaty had sent the wrong signal.

He said: i think that people...start to get worried and say: well if theyre prepared to opt out of a binding treaty with the eu, its the slippery slope.

The regions peace process was designed to keep borders and identity out of politics, mr houston added. brexit of course is all about borders and identity. it is bringing something that weve tried to... park, back into our everyday politics. in a divided society thats difficult.