U.K. Chancellor of the Exchequer Philip Hammond said Brexit will still go ahead in March 2019 in spite of disagreements in Prime Minister Theresa May’s cabinet over a transition period to help government and businesses adjust to the split.

Hammond, who is in Brazil to promote trade and economic ties, said the debate among leading lawmakers is about adjusting to a a new relationship with the European Union, not a question of staying longer in the 28-member bloc.

“It won’t be postponed or delayed. As Michel Barnier, the negotiator on the other side, the EU negotiator, says, the clock is ticking,” Hammond told reporters in Brasilia on Monday after meeting with Finance Minister Henrique Meirelles. “There is a discussion going on about how we will then move from full membership of the European Union to a future relationship with the European Union. That is a debate, a discussion that will go on through these negotiations.”

While Hammond and Home Secretary Amber Rudd have laid out a vision for a transition period post-Brexit allowing free movement of EU nationals to Britain to continue for up to three years, Trade Secretary Liam Fox told the Sunday Times it would “not keep faith” with last year’s vote to leave. Hammond has previously suggested a three- or four-year phase-in would be needed but others in the cabinet are pushing back to keep it as short as possible.

“The arrangements for our relationship with the European Union post-Brexit are the subject of a negotiation,” Hammond said.

May, who broke from her vacation on Monday to attend a ceremony commemorating Passchendaele, one of the bloodiest battles of World War I, refrained from wading into the latest Brexit squabble among her most senior ministers.

Her government is also studying a way to guarantee the rights of EU citizens modeled on the court that oversees relations between the bloc and Norway. Having said it wants to end the jurisdiction of the EU Court of Justice, May’s team may be willing to accept a body akin to the court of the European Free Trade Association, according to a person familiar with the matter.