British and EU negotiators are meeting again in Brussels for the second round of Brexit talks on the UK’s departure from the union.

The message from both sides: now is when the serious business begins.

The weekend saw more reports in the UK of a government split over future trading relations.

But first the talks will cover citizens’ rights, the bill the UK must pay, and what happens to the border between Northern Ireland outside the EU, and the Republic inside the bloc.

At a joint news conference both chief negotiators stressed the need to start tackling fine details.

“We will now delve into the heart of the matter. We need to examine and compare our respective positions in order to make good progress,” said the EU’s chief negotiator Michel Barnier.

“For us, it’s incredibly important we now make good progress, we will negotiate and identify the differences so we can deal with them and identify the similarities and we will enforce that and now it’s time to get down to work and make this a successful negotiation,” added his UK counterpart, David Davis.

There was no further comment from either side. It will be later in the week before both sides brief the media again (“Thursday”, Barnier said as the news conference ended, with Davis adding “work!” as they left the stage).

The news in the UK over the weekend focused on divisions within the Cabinet over the shape of a future Brexit deal. The Chancellor (finance minister) Philip Hammond has argued that a post-Brexit transitional agreement should remain in place for a couple of years, in the interest of business stability. His view is at odds with that of the Trade Secretary Liam Fox, who in an interview last week talked of a transition period of only “a few months”.

The immediate difficulties in Brussels include concerns over citizens’ rights and the exit bill. Prime Minister Theresa May’s proposals received a lukewarm reaction in Brussels and among campaigners for EU nationals in the UK and Britons in Europe.

On the question of the financial settlement, the UK has appeared to accept the principle of paying a bill; a written statement to Parliament last week recognized that “the UK has obligations to the EU”.

Earlier the Foreign Secretary Boris Johnson said the EU could “go whistle”, describing reported financial demands as “extortionate”. Barnier replied by repeating that the clock was ticking on the Brexit talks.