Welcome to the penultimate Guardian weekly Brexit briefing – after more than three and a half years and nearly 170 instalments, this newsletter will land in your inbox for the last time on 4 February, four days after Britain formally leaves the EU.

Full live and daily coverage of the talks on the future relationship between the bloc and its first ex-member will, of course, continue in the Guardian as they advance, while our Brexit Means … podcast will provide monthly in-depth insights.

As Britain gradually disengages from the EU, the Guardian’s European coverage will be developing and deepening. In the meantime, tap into the continental conversation on our Europe Now pages here, and subscribe to our fortnightly Europe newsletter.

Top stories

Boris Johnson’s Brexit bill cleared its last hurdle after the government overturned five House of Lords amendments. The Queen gave it her royal assent, making it law, and Conservative MPs cheered the European Union (Withdrawal Agreement) Act.

In Brussels, Ursula von der Leyen and Charles Michel, the European commission and council presidents, signed the withdrawal agreement with the EU’s chief negotiator, Michel Barnier, in attendance. “Things will inevitably change but our friendship will remain. We start a new chapter as partners and allies,” Michel said.

After it had crossed the Channel, the British prime minister then added his signature to the agreement in Downing Street, hailing a “fantastic moment” that he said would end years of “argument and division” and prove a positive change for the UK:

We can now move forward as one country – with a government focused on delivering better public services, greater opportunity and unleashing the potential of every corner of our brilliant United Kingdom.

In Davos, however, Sajid Javid had to tone down his comments the previous week to the effect that business leaders had better get used to life outside the single market and customs union. The UK would not diverge from EU regulations “just for the sake of it”, the chancellor promised.

Businesses were not overly reassured: the Institute of Directors warned it needed time to prepare for a new relationship with the EU by December, and demanded the government urgently publish its objectives for the next stage of the talks (the Brexit secretary, Steve Barclay, later said this would happen by early February).

Meanwhile, it emerged that the “straightforward” document that Northern Irish businesses will need to complete to send goods to Great Britain after Brexit (and which Johnson has said firms can throw in the bin) was in fact a complex form that includes 31 data elements.

Barnier and the Irish prime minister, Leo Varadkar, warned in Dublin that a united EU would continue to protect its members’ interests in the “very challenging” upcoming talks. Varadkar separately told the BBC the EU was likely to have “the upper hand”, and could use leverage over the financial industry to extract concessions on fishing.

Pascal Canfin, a leading French MEP and close ally of the president, Emmanuel Macron, reiterated that any attempt by the British government to seek full access to European markets without alignment on core EU standards for nature protection, climate, workers’ rights and state aid was “absurd” and would be voted down.

Barnier later rammed home the message, and also firmly rejected Johnson’s claims that there would be no checks on goods going from Great Britain to Northern Ireland after Brexit, saying the UK had agreed to them and they were “not dispensable”.

And British hopes of maintaining a post-Brexit flow of data with the EU, seen as vital for security and the economy, risked being jeopardised after the Netherlands raised questions over the UK’s poor record in protecting personal information.

What next

Brexit Day will be celebrated by leave voters on Parliament Square in London, and a clock counting down the last hour will be projected on to No 10 Downing Street, but 31 January will not be marked by any official pageantry.

As soon as the clock strikes 11pm (midnight in Brussels), the UK will no longer be a member of the EU and British citizens will no longer be EU citizens. Its 73 MEPs will no longer sit in the European parliament, British ministers will no longer sit in European council meetings.

Few others will notice much difference for the time being because the UK will remain part of the single market and customs union until the end of the transition period in December, so free movement of goods, people, services and capital will apply.

What happens after December 2020 remains unclear; the future relationship between the EU and its first ex-member remains to be negotiated. Much will depend on how far the UK government wants to diverge from the EU rulebook – whether or not it will abide by a “level playing field”.

Formal talks are likely to start in early March. David Frost, the prime minister’s chief Europe adviser, will lead trade negotiations with the EU on his behalf, at the head of a 40-person taskforce reporting into Downing Street. The Department for Exiting the EU (DExEU) is due to shut down on 31 January.

Here you will find a fairly exhaustive Guardian Brexit explainer on just how we got to this point, and what we can expect over the coming 11 months.

Best of the rest

Top comment

As we leave the EU, we should not forget what was gained while we were members, argues Andrew Rawnsley in the Observer:

For Brexiters, this Friday may be a night to revel. For the many who will feel a profound sense of loss, it will be an occasion for anguish. Indifference will be the least appropriate emotion. Dusk falls on a long, hugely significant and in many ways fruitful period of our modern history. What comes next, no one is sure, least of all those who most willed this rupture.

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Neat. On Philip Pullman’s grammatical objection to the new 50p coin: