LONDON (REUTERS) - Britain is due to leave the European Union on March 29, yet in reality the deadline for reaching an exit deal with the European Union is likely to be well before that date if Parliament is to pass necessary legislation in time.
The government plans to pass several pieces of major new legislation and hundreds of changes to existing law to adapt Britain to life outside the EU.
Prime Minister Theresa May is not expected to bring a deal back to Parliament before Feb 14, when she has promised that lawmakers will next get to debate Brexit. After that, Parliament has only 26 sitting days left before March 29.
Several previous Bills on Britain's relationship with Europe, including the 2018 EU Withdrawal Act, which transferred EU law into British law, have taken upwards of 30 sitting days to pass through Parliament.
Below is a summary of the Brexit-related legislation that the government intends to pass, although it has not been clear whether it believes all are needed by March 29.
EUROPEAN UNION (WITHDRAWAL AGREEMENT) BILL
Only needed if Britain is to leave with a deal, this Bill must pass in order for the Withdrawal Agreement with the EU to have domestic legal effect. But it cannot be introduced to Parliament until lawmakers have voted to approve the deal.
It gives effect to the transition period, due to run until December 2020, as well as the rights of EU citizens, a financial settlement with the bloc and an agreement on how to avoid a hard border in Ireland if a future trade deal with the EU cannot be concluded in time.
Many provisions are expected to be contentious, so the Bill's passage is unlikely to be quick.
This Bill focuses on transposing outside countries' trade deals with the EU into bilateral deals with Britain. It does not cover future trade agreements with the EU or others.
It sets up a Trade Remedies Authority and gives British authorities new power to collect and share information on exporters.
Trade minister Liam Fox says he is "increasingly confident" it will pass through Parliament by the time Britain leaves, but that otherwise there are contingency plans.
FINANCIAL SERVICES BILL
Only needed if there is no deal, it gives Britain power to implement and amend EU financial services regulations that have been agreed or are in negotiation and due to be implemented within two years of Brexit.
The following four Bills could probably be passed during a transition period. But if Britain looks set to leave the EU without a deal, the government may try to slim them down in order to rush them through.
Sets out farming and environment policy once Britain has quit the EU and its Common Agricultural Policy.
Creates a domestic fisheries policy governing foreign access to British fishing grounds, the licensing of fishing boats, and grants connected to fishing and marine conservation.
Ends free movement of people from the EU and repeals other EU law relating to immigration; protects the status of Irish citizens in UK immigration law; and gives Britain powers to amend EU law on social security coordination.
HEALTHCARE (INTERNATIONAL ARRANGEMENTS) BILL
Gives Britain power to fund and implement reciprocal healthcare schemes and share data. It is intended to allow the UK to maintain reciprocal healthcare arrangements with EU countries, but is not limited to the EU and could also allow Britain to implement new schemes with countries outside the EU.
In addition to new Bills, Parliament also needs to approve hundreds of changes to existing law to prevent legal "black holes" - where laws will fail to function or become invalid after Brexit.
These changes are made through "statutory instruments" (SI), subject to varying degrees of scrutiny by lawmakers.
They can be used to make changes such as altering the name of a regulator where a law refers to an EU body that will no longer be relevant to Britain.
The government estimates it needs to pass around 500 SIs by March 29.
As of Feb 5, 398 had been submitted and 119 had completed their passage through Parliament, according to the Hansard Society, a pro-democracy research body.
The government can, in an emergency, implement an SI with immediate effect, pending approval within a fixed period.
But it can only do that if the documents have been prepared, and parliamentary experts say government departments are having difficulty drafting them quickly enough.
DELAYING THE EXIT DATE
Having notified the EU of its intent to leave the bloc under Article 50 of the Lisbon Treaty, Britain must exit at 11 pm UK time on March 29, 2019 (7am Singapore time on March 30, 2019), unless the other 27 members agree to extend the two-year negotiation period.
Since that date is also enshrined in Britain's 2018 European Union (Withdrawal) Act, parliamentary approval would also be required to delay the departure.
If Britain leaves with a deal, it will continue to be bound by hundreds of EU international agreements during the transition period. If it leaves without a deal, these will immediately cease to apply, so a large number of replacement treaties will need to be ratified, either before or as soon as possible after March 29.