LONDON — Ireland’s prime minister has said the European Union will have the upper hand in upcoming negotiations on future relations.

The United Kingdom is due to leave the EU on Friday,. It then enters an 11-month transition period in which Britain will continue to follow the bloc’s rules while the two sides work out new deals on trade, security and other areas. Irish Prime Minister Leo Varadkar said Monday that “the European Union is a union of 27 member states. The U.K. is only one country.”

British Prime Minister Boris Johnson is adamant that he won’t agree to extend the Brexit transition beyond 2020, even if a deal has not been struck.

Varadkar said it will be difficult to secure a comprehensive agreement in time, and there’s a chance a deal might need to be approved by parliaments in all 27 EU countries.

“We need to get down to business very quickly trying to get that trade deal, which is absolutely essential for the Irish economy, as well as of course for Britain’s as well,” said Varadkar, battling to retain his job in a Feb. 8 election.