MPs are preparing to wage parliamentary warfare over Brexit as the much-delayed European Union (Withdrawal) Bill returns to the Commons on Tuesday.

What is it?

The EU withdrawal bill is the key piece of Brexit legislation, which aims to transfer EU law onto the domestic statute books after Britain formally leaves the bloc in March 2019.

Formerly known as the ‘Great Repeal Bill’ - or simply the Brexit bill - it will also repeal the European Communities Act of 1972, which gives EU law supremacy over UK domestic law.

The bill was announced in the Queen’s Speech in June, where the Government lays out its legislative agenda for the upcoming session.

Theresa May managed to see off a damaging Commons defeat in September when MPs backed the bill’s second reading by 326 votes to 290.

Theresa May's ability to deliver Brexit in doubt amid growing threat to her leadership

What happens next?

The legislation will enter its ‘committee stage’ on Tuesday, where it will receive line-by-line scrutiny by MPs to pinpoint any potential problems.

As it is such an important piece of legislation, it will have go before a ‘committee of the whole house’ where it is debated in the main chamber rather than in a smaller committee room away from TV cameras.

MPs are preparing for eight days in committee, starting this Tuesday and Wednesday, where there will be eight hours of debate each day on groups of amendments decided by Lindsay Hoyle, the deputy speaker.

The timetable for the remaining six days remain unclear as Parliament will be busy next week with the upcoming Budget.

Trouble ahead

Theresa May is facing intense pressure to shepherd the Brexit bill through the Commons and onto the House of Lords before March 2019, when the UK officially leaves the EU.

But opposition parties and rebel Tories have tabled hundreds of amendments and new clauses to the withdrawal bill as rival factions push their own Brexit agendas.

Pro-EU MPs and those favouring a softer Brexit have co-ordinated cross-party attacks on the bill, ranging from attempts to offer Parliament a vote on the final deal to the role of the European Court of Justice after Brexit.

Several Tory rebels, including former attorney general Dominic Grieve, are concerned over attempts to use so-called 'Henry VIII powers', which allow legislation to be passed with less scrutiny.

The Government insists it only intends to use these powers because of the sheer number of EU regulations it needs to tackle, but Labour has warned that the plans amount to a significant power grab by ministers.

Labour's shadow Brexit secretary Sir Keir Starmer has tabled a key amendment calling for Britain to remain in single market during a two-year transition period, as many MPs believe Britain will not have time to secure a vital trade deal with the EU before 2019.

Ms May's weakened Government could face embarrassing defeats if MPs force votes on some of these key issues, and receive enough backing from the Tory benches.

Brexit: the deciders Show all 8 1 /8 Brexit: the deciders Brexit: the deciders European Union's chief Brexit negotiator, Michel Barnier Getty Brexit: the deciders French President Emmanuel Macron Getty Brexit: the deciders German Chancellor Angela Merkel Reuters Brexit: the deciders Commission President Jean-Claude Juncker EPA Brexit: the deciders The European Parliament's chief Brexit negotiator Guy Verhofstadt Getty Brexit: the deciders Britain's Prime Minister Theresa May Getty Images Brexit: the deciders Britain's Chancellor of the Exchequer, Philip Hammond PA Brexit: the deciders After the first and second appointed Brexit secretaries resigned (David Davis and Dominic Raab respectively), Stephen Barclay is currently heading up the position PA

What happens next

Once it passes the committee stage, the Brexit bill will go through the report stage where all the amendments are considered.

The bill will then have a third reading in the Commons before it heads to the House of Lords for scrutiny.

Its passage through the Lords will likely heap further misery on Ms May as the Tories do not have a majority in the upper chamber. The Independent recently revealed that peers are preparing to join forces to inflict defeats on the Government.