She might gamble on calling another election to try and win a bigger majority, or there is even the option that after two-and-a-half years of failing to find a Brexit agreement that Parliament supports, a completely new referendum on the topic could be held-something which would outrage Brexit supporters.

Ahead of the debate, the signs for May have looked increasingly ominous, with opposition mounting against her, from opposition parties and also inside her own Conservative Party.

Her government is propped up by the support of 10 MPs from Northern Ireland's Democratic Unionist Party, known as the DUP, and the issue of the post-Brexit status of the border between Northern Ireland and the Republic of Ireland, an EU member state, has been one of the biggest stumbling blocks for all negotiations.

Earlier this week, members of the DUP along with representatives of the Labour Party, the Scottish National Party, the Liberal Democrats, the Green Party and Wales's Plaid Cymru signed a letter accusing the government of being in contempt of Parliament for failing to reveal the full legal advice it had received on the impact of Brexit.

Explosive events

Having then lost a vote on the issue, the government became the first in history to be found guilty of such a charge, and was duly forced to reveal the suppressed information.

These explosive events in the buildup to the debate mean projections of what Brexit outcomes Britain might secure are now even more speculative than ever.

One option popular among MPs looking for the softest possible Brexit is known as "Norway Plus".

Norway, along with non-EU states Iceland and Liechtenstein, and the 28 EU member states, is part of the European Economic Area, known as the EEA. This gives access to the EU's single market, while abiding by the internal market's rules on free movement of goods, people, services and capital.

It also covers cooperation in fields such as consumer protection, education and the environment but Norway is not part of the EU lawmaking process and is not covered by EU rules on topics including common agriculture and fisheries policies, the customs union or monetary union.