BRUSSELS (AP) — The European Union’s top officials have formally signed the post-Brexit trade deal with the United Kingdom.

European Commission president Ursula von der Leyen and European Council president Charles Michel put pen to paper on Wednesday morning during a brief signature ceremony in Brussels. The documents will then be flown across the Channel to London in a RAF plane for British Prime minister Boris Johnson to sign them.

The U.K. Parliament will later start debating the agreement setting up new trade rules between the 27-nation bloc and former member Britain. The agreement needs approval from Britain’s Parliament, and from the EU’s legislature, which is not expected to take up the deal for weeks.