It is likely to put her in conflict with the European Union, which has been pushing for Mrs May to delay the cut-off date until 2019. However ministers have raised concerns that waiting until the end of negotiations will lead to a huge surge in the number of EU migrants coming to the UK before Brexit.
The cut-off date for the 1.2million British nationals living in other EU countries will ultimately be decided by Brussels. The European Parliament's chief negotiator has suggested that the EU will offer British people to individually opt-in and remain European citizens.
This will make huge difference to Britons travelling abroad for work as well as I guess Erasmus students as well.
www.telegraph.co.uk/news/2017/02/26/theresa-may-poised-announce-end-free-movement-new-eu-migrants/