The UK and the European Union have agreed a major new deal covering areas including trade, defence, fishing and energy.
However, negotiations are still taking place on a number of key issues – leaving some important questions unanswered.
How much will the UK pay?
The deal makes several references to a "financial contribution" from the UK to access certain benefits, notably an agreement to reduce checks on food exports to the EU.
The prime minister's official spokesman said these were "administrative costs".
He insisted they would not be "big" but refused to put a figure on how much the UK would pay.
In other areas, terms are still being negotiated so the cost to the UK isn't known yet.
For example, the two sides are working towards the UK rejoining the Erasmus+ exchange programme, which allows students to study or do work placements abroad.
Rather than simply covering administrative costs, the UK would be expecting to get direct benefits in return and the government has said it will only take part "on significantly improved financial terms".