MPs will have their say on the next steps for Brexit later as Theresa May urges them to "do their duty".

Writing in the Daily Mail, the prime minister said the UK remained "firmly on course" to leave the EU with a deal "if MPs hold their nerve".

A number of amendments to the government negotiating strategy will be voted on in the Commons on Wednesday.

The votes are not on Mrs May's Brexit deal itself, but they will show what support she can or cannot get.

After her Brexit deal was overwhelmingly rejected by MPs last month, the prime minister has been trying to seek assurances from the EU to address MPs' concerns.

She is still in talks with Brussels over the Irish backstop policy in her plan - which aims to prevent a hard border returning to the island of Ireland - and has assured MPs they will get to vote again on the deal by 12 March - just 17 days before the UK's scheduled leaving date.

However, on Tuesday, Mrs May bowed to pressure to accept that the 29 March deadline might not be achievable, and promised MPs a vote on whether or not to delay Brexit or rule out leaving the EU without a deal if her plan is rejected for a second time.

In the Mail, Mrs May stressed that she did not want to see the Article 50 process extended and her "absolute focus" was on getting a deal in place for 29 March.

The prime minister's critics have accused her of "kicking the can down the road", but she insisted her efforts to persuade the EU to make concessions had "already begun to bear fruit".

What does it mean to table an amendment?
The process starts with the government putting down a motion. It is a plain piece of text, asking the House to note the prime minister's most recent Brexit statement - made on Tuesday - and that discussions between the UK and the EU are ongoing.

This then allows MPs to table amendments - alternative options - to that motion, setting out their proposals on what they think should happen next.

Speaker John Bercow makes the final call on which amendments are put to a vote, and we won't know which ones he has chosen until later on Wednesday. Voting is likely to take place around 19:00 GMT.

Labour has tabled an amendment calling on the House to support its alternative Brexit plan, which would include a "comprehensive customs union" and close alignment with the EU in the future.

This would mean no customs checks or charges would be imposed on goods moving between the UK and the rest of Europe.

If that proposal is voted down, Jeremy Corbyn has said the party would move to formally back another referendum "in order to prevent a damaging Tory Brexit" or no-deal outcome.

Mrs May criticised the Labour leader's approach, saying "his cynical political games would take us back to square one."

"Instead, Parliament should do its duty so that our country can move forward," she said.

The other 11 amendments - named after the MPs or groups which propose them - that have been tabled include:

The Independent Group amendment - The former Labour and Conservative MPs call on the government to make time in Parliament before 8 March to debate and decide what steps are necessary to prepare for another EU referendum

The Alberto Costa amendment - This seeks to protect the rights of UK citizens in the EU, and vice versa, regardless of the outcome of UK-EU negotiations

The Cooper amendment - This calls on the government to bring forward a motion on whether Parliament wants to seek a "short limited extension" to Article 50 if the prime minister's deal is rejected and if the House then rejects leaving without a deal. It reiterates the statement made by Mrs May on Tuesday.

The Caroline Spelman/Jack Dromey amendments - The first is to give over the parliamentary schedule to MPs for a day to enshrine in law a vote on extending Article 50. Their second amendment would put aside Tuesday 19 March to have a debate and to hold a vote on the form of the future relationship, which could be an indicative vote. Following Tuesday's announcement from Mrs May, they are not expected to put their amendments to a vote.

Mrs May said any delay to the UK's departure should not go beyond the end of June and "would almost certainly have to be a one-off".

Extending Article 50 would require the unanimous backing of the other 27 EU member states - something they have indicated they would be happy to do.

BBC political editor Laura Kuenssberg says it is now extremely unlikely that the UK will leave at the end of March without a deal.