What does triggering Article 50 mean for our consumer rights?
When Theresa May triggers Article 50 on Wednesday, she starts a countdown that will see the UK leave the EU in 2019.
During the run-up to the referendum, Brexit campaigners complained of 'red tape' hampering British business, claiming that as much as two thirds of British law is derived from the EU.
It's not a claim that stands up to fact-checking: it includes product regulations as well as laws, including plenty that don't even affect the UK - standards for olive oil production for example.
47% of parents think Brexit will leave children worse off, report finds
But all the same, there's no doubt that much consumer law, including rights we've been used to for years, is derived from European legislation. So where do we go from here?
There's concern that chasing trade with the US will mean accepting the US's far lower levels of food safety. It would mean we'd have to put up with unlabelled genetically modified food, for example, along with chicken washed in chlorine, and meat from animals permanently dosed with antibiotics.
And more general consumer rights could be under threat too.
"For over 40 years, EU consumer policy has led to a strong set of consumer rights and protections," says the European Consumer Organisation (BEUC).
"Across the EU, consumers can return a good they purchased online within 14 days of the sale. Chemical products need to meet robust safety standards before being marketed in the EU. Thanks to the cooperation between market watchdog bodies, unsafe products can be removed swiftly from any shop in the single market. Food products can only carry health claims if they are scientifically proven (for instance 'this product will strengthen your immune system'). It is unclear how Brexit will impact on these achievements."
Third of businesses already feeling Brexit pain
However, the most important thing to note is that, thanks to the Great Repeal Bill, all EU law is enshrined in British law for the time being, meaning that your rights won't change for at least the next two years.
And, depending on the terms on which we leave, the chances are that much consumer law will stay the same afterwards. If the UK wants to continue trading with the EU - a far more important market than the US - we will need to carry on offering similar levels of consumer protection.
"However, over this period, uncertainty will remain over live EU issues," says Marzena Lipman, policy manager with the Citizens' Advice Bureau.
"This includes the EU regulations which were adopted by the European Parliament, but have not been implemented yet in the UK law such as the EU data protection rules, the revised Payment Service Directive; or other regulatory proposals which are in the pipeline (for example the EU telecoms regulations)."
Can you beat the Brexit bill for this year's holiday?
Meanwhile, many rights that we currently enjoy when travelling are under threat - and the bad news is that these are much less likely to be retained after we leave the EU.
EU legislation sets a minimum level of protection over issues such as delays, cancellations, damaged luggage or special mobility needs. For example, under EU rules, passengers can claim compensation for certain flight delays within the EU and between EU and non-EU airports.
Whether or not we keep these rights depends on the deal Theresa May signs. If, like Norway for example, we sign a constitutional treaty with the EU without being a member, passengers will continue to receive compensation for delayed, cancelled or overbooked flights. However, under the hard Brexit May has signalled she's planning, most of these rights could vanish. While passengers flying into the EU would in theory still have some protection, they might have to go to court in another country to receive compensation.
Currently, the European Health Insurance Card (EHIC) entitles UK citizens to free or reduced-cost treatment in other EU countries. It's highly unlikely that this system will be continued unless EU citizens are given equivalent access to the NHS.
Phone roaming charges
Over the last few years, the EU has gradually forced phone companies to reduce their roaming charges - and to pledge to eliminate them altogether by June this year. However, once the UK leaves the EU, companies won't have to offer this to UK citizens - and if they don't have to, the chances are they won't.
All in all, many Brexit campaigners have been keen to get rid of what they see as a European stranglehold on British law. However, it's worth remembering that, like the 'red tape on businesses' that gives disabled people equal employment rights and guarantees sick pay and maternity pay, most consumer law brings far more benefit than harm to British people.
As a result, organisations such as Which? and Citizens Advice have pledged to keep fighting to retain our rights, whatever May decides.
Says Citizens Advice: "Whatever the outcome of the Brexit negotiations, Citizens Advice will work with the government and other stakeholders to ensure that consumer protections remain strong post Brexit."