The UK’s chief Brexit negotiator has said the government is not “scared” of walking away from talks without a trade deal ready to come into force in 2021.
David Frost told the Mail on Sunday the UK would leave the transition arrangement - which sees it follow many EU rules - “come what may” in December.
In contrast, he said Theresa May’s team had “blinked and had its bluff called”.
EU negotiator Michel Barnier has said he is “worried and disappointed” about a lack of concessions from the UK.
He was speaking after informal talks between the pair failed to find a breakthrough.
An eighth round of formal negotiations begins on Monday.
Both sides want a deal agreed next month in order to have it signed off by politicians on both sides of the Channel by the end of the transition period on 31 December.
Differences remain on issues such as fishing and the level of taxpayer support the UK will be able to provide for businesses once it is an independent nation.
Lord Frost told the newspaper: “A lot of what we are trying to do this year is to get them to realise that we mean what we say and they should take our position seriously.”
Analysis by Chris Mason, Political Correspondent, BBC News
The UK left the European Union in February but until the end of December it is in a transition period, where very little has actually changed.
The time left to negotiate a long-term arrangement between London and Brussels is tight, and the language from Lord Frost is defiant.
“We are not going to be a client state,” he says. “We are not going to accept provisions that lock us into the way the EU do things.”
While this is his first interview since the UK left the EU, officials in Brussels are familiar with his arguments. One described the remarks as “unsurprising muscle-flexing”.
Sources there say what they can’t accept is the UK having the freedom to undercut businesses on the Continent in their own Single Market.
The time for compromise is running short. That doesn’t mean it won’t happen, but there’s no guarantee it will.
In the interview, Lord Frost said wanting control over the country’s money and affairs “should not be controversial”.
“That’s what being an independent country is about, that’s what the British people voted for and that’s what will happen at the end of the year,” he said.
“I don’t think that we are scared of this at all. We want to get back the powers to control our borders and that is the most important thing.”
The government was “fully ready” to trade with the EU without a formal deal, he said.
In practice, this would mean taxes on exports and customs checks.
It’s a scenario which road hauliers say would cause “severe” disruption to supply chains, with border management systems not yet up and running to make sure consignments are cleared to proceed to the EU.