Why there's more to the Northern Ireland bill than meets the eye
The Northern Ireland Executive Formation Bill could bring up many more issues than the government intends.
The bill itself is the measure to keep government in Northern Ireland ticking over while the devolved executive remains absent - it has not functioned since March 2017.
But, as it is a piece of legislation, MPs are allowed to put forward amendments to the bill and try to further their own campaigns in the process.
Let's be clear - putting forward an amendment does not mean it will form part of the bill.
It is up to the Speaker, John Bercow, to choose which amendments go forward on Tuesday and then it will be down to votes in the Commons.
But, if chosen, there are three amendments that could make this bill more than just a straightforward government measure.
1) Same-sex marriage
Despite legislation coming into force in 2014 to make same-sex marriage legal in England and Wales, and separately in Scotland, it still remains illegal in Northern Ireland as it is a devolved issue.
There have been five votes on the matter in the Northern Ireland Assembly since 2012, and despite the final vote in 2015 in favour of bringing in the law, it was vetoed by the Democratic Unionist Party.
Labour's Conor McGinn has put forward an amendment to this bill that, if approved, would see legislation put down to extend the law to Northern Ireland by the end of October - if an executive hasn't been formed by 21 October.
"We all want to see the institutions at Stormont up and running and taking decisions like these," he said.
"But two and a half years after the executive collapsed, LGBT people in Northern Ireland are still being denied the same rights as citizens in the rest of the UK and island of Ireland.
"How much longer should they wait for equality?
"My amendment mirrors the government's deadline of 21 October to see progress made and devolution restored. If that hasn't happened by then, Westminster should and must act."
Abortion is also not legal in Northern Ireland, as the 1967 Abortion Act does not extend across the Irish Sea.
Instead, the 1861 Offences Against the Person Act is still in place, which makes it illegal for women to get an abortion or for others to help them.
A termination is permitted in extreme cases, such as if a woman's life is at risk or if there is a risk of permanent and serious damage to her mental or physical health - but in the latest statistics from the Department of Health from 2017/18, this lead to just 12 abortions being carried out.
Women are able to travel to England to have the procedure and, after legislation brought in 2017, the cost is covered by the NHS.
But a number of MPs have been arguing for the law to be extended to Northern Ireland.
Labour's Stella Creasy is putting forward an amendment to the bill to make that happen.
"All those concerned about human rights violations in Alabama need to look closer to home and that's not just what I think," she said.
"According to the UN, women in Northern Ireland face 'grave and systematic' human rights violations because we treat them as second class citizens and deny them their basic human right not to be forced to continue an unwanted pregnancy.
"It's time this government stopped hiding behind devolution to defend this situation and please the DUP.
"With women facing jail now in Northern Ireland and no sign of an Assembly anytime soon at Stormont, this vote is a chance for Parliament to uphold our human rights obligations and treat every woman in the UK with equal respect by ensuring they can access a safe, legal and local abortion if they want to do so."
3) Blocking a no-deal Brexit
As the Tory leadership contest continues, a lot of talk has been focused on whether the next prime minister would suspend Parliament - known as prorogation - to make sure MPs don't stop a no-deal Brexit.
But a number of Remain-leaning MPs are trying to find ways to prevent it from happening.
Tory MP and former Attorney General Dominic Grieve is one such Remainer.
Although he has yet to publish his amendment, he told BBC Radio 5 Live's Pienaar's Politics that it will seek to ensure Parliament comes back to the Northern Ireland issue in October - and that means Parliament must be sitting - so, in theory, it cannot be prorogued.
He told the programme it was a "perfectly legitimate place" for the amendment, adding: "We're going to have, in the course of the next 24 hours, an important bill on Northern Ireland.
"Northern Ireland and Brexit go rather closely together.
"The chances are, if a [no-deal Brexit] goes through... it is going to be the end of Northern Ireland's union with the United Kingdom, with serious political consequences flowing from it."