Brexit is scheduled to become effective at the end of 29 March 2019 and will take place either with a Withdrawal Agreement or without one having been entered into between the UK and the EU-27. At this point in time it is possible that the Article 50 TEU notice is withdrawn by the UK Government. Whether the Brexit Date 29 March 2019 is postponed upon application of the UK and agreed with the unanimous consent of the other 27 Member States is still undecided.
Upon Brexit becoming effective the UK will cease to be party to the existing Free Trade Agreements and Association Agreements the EU currently has entered into with a multitude of countries and regional free trade zones around the world in the last decades. The UK is currently striving to enter into its own binding agreements with such other countries to come into force on 30 March 2019 but so far only continuity agreements with Switzerland and a number of smaller UK trading partners have been inked.
There is no difference between a “Deal” and a “No Deal” Scenario in relation to the termination of the existing Free Trade Agreement and Association Agreements on 29 March 2019. Even if the UK House of Commons should change its mind and ratify the Withdrawal Agreement, and even if the Transition Period until 31 December 2020 contemplated in the Withdrawal Agreement under Articles 126 and 127 thereof would then come into force, such Transition Period only applies in the relationship between the UK and the EU-27, but does not bind any other country around the world without their express consent.