May dashed to Strasbourg on May 11 and in a late night news conference announced she had secured legally binding reassurances on the so-called Northern Irish border backstop, an insurance policy aimed at avoiding post-Brexit controls on the United Kingdom's border with EU-member Ireland.
Many Brexiteers and the DUP fear the backstop will trap the United Kingdom in the EU's orbit, and have sought guarantees it will not.
But the new documents were not enough to sway the most eurosceptic wing of her party and the DUP, and the deal was voted down again on March 12.
In the following days lawmakers voted to avoid a "no-deal" Brexit and to ask for a delay to Brexit.
By law, Britain is due to leave at 2300 GMT on March 29, 2019, the end of next week. But May has said that she will ask for a delay until June 30 if parliament approves a deal by Wednesday.
"Such a short technical extension is only likely to be on offer if we have a deal in place," May said on March 13.
"The House has to understand and accept that, if it is not willing to support a deal in the coming days, and as it is not willing to support leaving without a deal on 29 March, then it is suggesting that there will need to be a much longer extension to Article 50."
