LONDON, United Kingdom (AFP)— Britain said Thursday it was “very likely” a Brexit trade deal would not be secured without a significant shift from Brussels, after Prime Minister Boris Johnson spoke to EU chief Ursula von der Leyen.

“The Prime Minister underlined that the negotiations were now in a serious situation. Time was very short and it now looked very likely that agreement would not be reached unless the EU position changed substantially,” a Downing Street spokesperson said.

“The Prime Minister repeated that little time was left. He said that, if no agreement could be reached, the UK and the EU would part as friends, with the UK trading with the EU on Australian-style terms,” the spokesman added.

He noted both leaders agreed to remain “in close contact”.

Downing Street said Britain was making every effort to accommodate “reasonable” EU requests over so-called level playing field provisions governing fair competition.

But it added that some “fundamental areas remained difficult” over the issue.

It also noted disagreements over post-Brexit fisheries were a key obstacle, with Johnson stressing Britain could not accept limits on its sovereignty.

“The EU’s position in this area was simply not reasonable and if there was to be an agreement it needed to shift significantly,” the statement read.

Britain formally left the EU at the end of January, but is bound by most of its rules until December 31 as the two sides try to agree the terms of their future trading relationship.

However, talks have been gridlocked for months, with London and Brussels appearing to be dug in over their respective stances on fishing and competition rules.