This replaced the Brexit transition deal and restored Britain’s place as a fully independent trading nation. The UK withdrew from the European single market and stopped implementing laws made in Brussels.
However Boris Johnson agreed to some customs checks between Northern Ireland and the rest of the UK, infuriating unionists.
Speaking to PoliticsHome Vale de Almedia, the EU’s most senior diplomat in the UK, admitted there are still tensions between Britain and the bloc.
He claimed there remains a “gap of understanding” about what parts of the agreement mean.
Exports of some UK farm produce to the EU fell significantly after Brexit as new checks were imposed.
Mr de Almedia argued these are an inevitable impact of Britain leaving the single market.
He commented: “Decisions have consequences and one needs to be aware of that.
“What we need to distinguish between is temporary issues and structural issues that will not go away with time, which are linked to the UK decision to leave the Single Market and the Customs Union.”
Some of the worst tension have been over Northern Ireland with the UK unilaterally deciding to delay introducing some customs checks.
This infuriated the EU which launched legal action against Britain.
However it didn’t placate the unionist community with the DUP calling for the Northern Ireland backstop to be scrapped in its entirety.
Loyalist rioting which broke out across Northern Ireland last month was blamed in part on anger at the new checks.
Mr de Almedia insisted the EU wants to ensure peace in Northern Ireland but didn’t offer any concessions.
He said: “We are committed to peace and prosperity in Northern Ireland.
“We are emotionally and politically committed to Northern Ireland.
“We have been sponsors and supporters of the Good Friday Agreement since the beginning and we are still there and attentive.”
On Thursday dozens of French fishing boats protested off Jersey after post-Brexit rules tightened access to the island’s fishing stocks.
Under the Brexit deal French vessels can still access UK waters until 2026 but only if they can prove they’ve been historically active in these areas.
Some smaller French vessels claim they are unable to provide the proof required by the British authorities.
Mr de Almedia played down the clash and insisted it can be resolved diplomatically.
The Portuguese diplomat stated: “This relationship should not be hijacked by accidents or flare-ups.
“It's for politicians and diplomats to make sure that is the case.”
Mr de Almedia was recently granted full ambassador status by the Government.
It had originally refused, on the basis that the EU is not a country, infuriating Brussels.