MPs in Britain voted on Wednesday in support of Prime Minister Theresa May’s plan to trigger Article 50 of the Treaty of Lisbon by March end, which will initiate the process of the country’s exit from the European Union. The MPs voted by a near-400 majority in support of May’s plan but with the stipulation that she must first make her Brexit plan public, The Guardian reported.

Article 50 of the treaty signed by EU members contains the rules that a country leaving the 28-state block must follow. If things go as May has planned, the United Kingdom will no longer be part of the European unit by the end of March 2019. On October 2, May had said they will begin the process of exiting the EU by the end of March 2017.

The Opposition Labour Party, however, laid out five conditions for its support for the prime minister’s Brexit plan. Shadow Brexit secretary Sir Keir Starmer said the government would face “further challenge” from the Labour Party if it did not meet their terms.

The Supreme Court of the United Kingdom is in the process of hearing the government’s appeal on who has the authority to trigger Article 50 – the government or Parliament. The government had approached the top court after a UK high court had ruled that a Parliament vote was needed to trigger Article 50. If the Centre loses the appeal, it will have to pass an Article 50 Bill to initiate the Brexit process. Starmer said the Labour Party would amend the Bill to include its conditions if the government did not include them.

The Labour terms include: ensuring detail and clarity in the proceedings; allowing relevant parliamentary bodies to examine the plan; enabling the Office for Budget Responsibility to look into the plan’s sustainability in terms of public finances; including details to clarify that the concerns of Scotland, Northern Ireland and Wales are being taken into account; and providing details to build a “genuine consensus”.

The UK had voted to leave the EU in a referendum on June 24, after which David Cameroon, who had campaigned for the country to remain in the bloc, resigned as prime minister. The UK government had rejected a petition calling for a second referendum. May took charge on July 11 to implement the result of the vote along with her team.