The UK is due to leave the European Union at 23:00 GMT on 29 March.
If Prime Minister Theresa May is unable to win the backing of Parliament for a revised withdrawal agreement, MPs will be asked to vote on whether the UK should leave the EU without a deal instead.
So if we end up with no deal, how could it affect you?
1. The contents of your shopping basket may change
What you find on the supermarket shelves could well be where you see the first effects.
About 30% of our food currently comes from the EU, and it is likely that some foods, such as fresh vegetables and fruit, will become more expensive in the event of no deal.
Increased import taxes and transport delays could all mean a rise in prices. And if a no-deal Brexit was followed by a fall in the value of the pound, that would also have the same effect.
Supermarkets themselves have already warned that there could be empty shelves and higher prices.
And Bank of England governor Mark Carney has said that, in a worst-case scenario, our shopping bills could increase by 10%.
The government has said that while a no-deal Brexit alone won’t lead to food shortages, consumer behaviour could. Panic buying could mean food retailers run short of some products.
Supermarkets say they have been stockpiling some foods – but they are unable to do that for fresh fruit and veg.
There have also been warnings about possible price rises for dairy goods.
A no-deal Brexit could mean the UK has to pay tariffs, or taxes, of up to 35% on products such as cheese and butter, but it is thought unlikely that retailers would pass all of this increase on to the customer.
- Government advice for the food and drink sector
2. You will need to take extra measures when travelling to Europe
Millions of people from the UK travel abroad each year – the vast majority of journeys made to Europe.
If you are planning to make a journey to an EU member state after 29 March, the government is advising you to check you have the right paperwork.
Flights and Eurostar:
The government and the Association of British Travel Agents (Abta) have both said that flights to and from the UK would still operate in a no-deal scenario.
And Eurostar bosses have said they are working to ensure their services run as smoothly as possible, despite a government assessment that warned of long queues at London’s St Pancras International, the main Eurostar terminal in the UK.
In terms of paperwork, you won’t need a visa for stays in countries in the Schengen area – where passports are not required and all other types of border control have been abolished (full list here) – of up to 90 days out of any 180-day period. However, you may need a visa if you intend to stay for longer.
The government is also advising you to make sure your passport is valid for at least six months if you are travelling to the Schengen area.
Until recently, UK citizens who renewed their passport before it expired could have up to nine months of the remaining validity added to their new travel document.
But the government has now warned that this time carried over will not count towards the six-month requirement after a no-deal Brexit. You can check if your passport has enough time left with this government tool.
For countries that are in the EU but not in the Schengen area (Bulgaria, Croatia, Cyprus and Romania), you’ll need to check the entry requirements for the country you’re travelling to before you travel.
Travel to Ireland is subject to separate Common Travel Area arrangements, which will remain the same after the UK leaves the EU.
If you have a UK bank account and intend to use your bank card to pay for goods and services while you are in the EU as well as Iceland, Liechtenstein and Norway (the European Economic Area), the government has warned that it may become more expensive.
European health cover:
In addition, if there is no deal, then in theory the cover provided by your European Health Insurance Card (EHIC) would cease to exist.
The government is advising travellers to buy insurance to cover health care “just as you would if visiting a non-EU country”.
If you intend to drive in the EU after exit, you may need an International Driving Permit and a green card from your insurer.
- Full government travel advice
- How will it affect my holidays to Europe?
3. You may need to check medication is available and it may be more expensive
Ministers and NHS leaders say every effort is being made to ensure there will be enough medicines and clinical equipment available in the event of delays to imports from the EU.
Measures taken include:
- a six-week stockpile of essential medicines
- a plane chartered to fly in drugs that can’t be stockpiled
- warehouses with refrigeration capacity rented
- ports other than Dover and Folkestone prepared to take ferries with lorries carrying imported medical supplies
However, the Royal Pharmaceutical Society warned in January that pharmacists were struggling to obtain common medicines – including painkillers and anti-depressants.
While there are regular fluctuations in medicine supplies, there are concerns a no-deal Brexit could make shortages worse.
Pharmacists have advised patients to order medicines in advance to give them time to deal with requests.
And the Royal College of Radiologists has told doctors to prepare for delays in some drugs used to detect cancer, by reducing their workload in the days after 29 March.
- Full government health advice
- Should NHS patients be worried?
4. UK nationals living abroad may have to take extra measures
About 1.3m UK-born people live in the other 27 EU countries.
The government is advising UK nationals living in the EU, the EEA or Switzerland to take steps to prepare for a no-deal Brexit. These will differ according to the country you are living in.
The priority for most will be to register as residents, but the rules – including deadlines for paperwork – vary from country to country.
There is country-specific government advice here.
UK nationals living in, working in, or visiting the EU may find that their access to healthcare in EU member states will change after 29 March.
If you are eligible, you should register for healthcare under your country’s local rules. You may have to be a long-term legal resident or pay social security contributions to access free or discounted healthcare.
The government recommends that you get health insurance while you are applying for residency.
UK students studying abroad are also advised to buy health insurance.
Information on how to access healthcare abroad can be found on the NHS website.
The UK government will continue to pay state pension, child benefits, and disability benefits to eligible UK nationals in the EU.
The UK’s exit from the EU will not change existing double taxation arrangements.
These ensure that everyone – not just British citizens – living in a country that has a treaty with the UK will not pay tax in two countries on the same income/gain, and determine which country has primary taxing rights.
- Full government advice for UK nationals living in the EU
- How would no deal affect UK citizens in the EU?
5. EU citizens need to apply for ‘settled status’
The UK government has reached an agreement with the EU, as well as Norway, Iceland, Liechtenstein, and Switzerland, that will protect the rights of EU citizens and their family members who are living in the UK.
There are currently 3.8 million EU citizens living in the UK.
If you are an EU citizen and living in the UK, the government has a tool to find out what you need to do and when.
- Government advice on applying for settled and pre-settled status
6. Importing goods may get more expensive
Importing goods from the EU is likely to get more expensive when free movement of goods ends with the UK’s departure.
As a member of the EU, UK firms don’t have to pay extra duties, taxes or have customs checks on goods travelling to or from the EU.
But after a no-deal Brexit, new rules will apply.
Government advice on how firms should prepare for this scenario can be found here.
- Firms told to prepare for no-deal Brexit
7. House prices could be affected
Most commentators and industry experts agree that uncertainty created by the Brexit process is causing buyers and sellers to sit tight, causing a slowdown in the housing market.
UK house prices grew at the slowest annual rate for nearly six years in January, according to the Nationwide.
The Nationwide said it was likely that the recent slowdown in the market was due to “the impact of the uncertain economic outlook on buyer sentiment”.
The Bank of England says the impact of the UK leaving the EU on the housing market could be significant.
It has said that house prices could fall by up to 30% from their pre-Brexit level if there was no deal, or a so-called “disorderly Brexit”.
Property agents Savills suggest buyer confidence will have a bigger role to play than affordability in house price movements this year.
- Will the value of your home change in 2019?
8. Mobile phone roaming charges may rise
Using your mobile phone in the EU may be more expensive in the event of a no-deal Brexit, the government has warned.
The amounts EU mobile operators would be able to charge UK operators for providing roaming services would no longer be regulated after 29 March.
Digital, Culture and Media Secretary Jeremy Wright has said that, although mobile operators will be able to implement roaming charges if they want to, the government would be legislating to put a £45-a-month limit on the amount customers could be charged.
To be safe, the government advises you to understand how to turn off data roaming on your mobile if you are worried about being charged.
- Government advice on mobile roaming
- What will happen to mobile roaming charges after Brexit?
9. Some ports and motorways could see extra delays
Transport Secretary Chris Grayling has said there could be freight traffic disruption in Kent in the event of a no-deal, if additional customs checks are introduced in Calais, Coquelles and Dunkirk – where freight services disembark.
At the moment, freight vehicles going through Dover are subject to passport and security checks.
But under a no-deal scenario, EU-bound lorries will also need to complete customs declarations, and certain goods may also require physical checks, and this could lead to bottlenecks.
In this scenario, a traffic management system known as Operation Brock would come into force on a section of the M20. Traffic would be allowed to flow in both directions on the same carriageway, while lorries would be left queuing on the other side.
If that proved to be insufficient, a disused airfield near Ramsgate would be used as a lorry park, and if further capacity was still required, the M26 could also be used.
- Could leaving with no deal cause traffic jams?
- Could Channel Ports cope with no deal?
10. UK students studying in the EU and EU students studying in the UK face a period of uncertainty
More than 16,000 British students studied on placements organised by the Erasmus study abroad scheme – in place since the 1980s – in 2016-17.
UK universities say they would expect a similar number to be planning to do the same this coming academic year.
The government is committed to funding everything that has already been agreed, so people who have already started Erasmus trips will be able to continue them.
But if the UK leaves the EU without a deal before the exchanges for the next academic year have been finalised, then the government would need European agreement to keep taking part. It has issued a technical note explaining this.
That is true for both UK students planning to go to EU countries, and EU nationals hoping to come to the UK.
Meanwhile, Universities UK has launched a campaign supporting opportunities for studying abroad.
- What will happen to the Erasmus scheme after Brexit?
Remind yourself of the Brexit basics with:
- A simple guide to the UK leaving the EU
- A jargon-busting guide to the key terms