The chief Brexit negotiator said the government was not “afraid” to pull out of the talks without a trade deal ready to go into effect in 2021.
David Frost told the Mail on Sunday that the UK will leave the transitional arrangement – which he believes follows many EU rules – “what might happen” in December.
In return, he said, Theresa May’s team “blinked and was called out to deceive.”
European Union negotiator Michel Barnier said he was “concerned and disappointed” about the lack of concessions from the UK.
He was speaking after the informal conversations between the spouses failed to achieve a breakthrough.
The eighth round of formal negotiations starts on Tuesday.
The two sides want an agreement next month to be signed by politicians on both sides of the channel by the end of the transition period on December 31.
Disputes remain over issues such as fishing and the level of taxpayer support the UK will be able to provide to companies once it becomes an independent country.
Lord Frost told the newspaper: “Much of what we’re trying to do this year is get them to realize that we mean what we’re saying and they should take our position seriously.”
“Unsurprisingly flexing muscles”
Analysis by Chris Mason, BBC News political correspondent
The UK left the European Union in February, but until the end of December it is in a transition phase, with very little already changed.
Time left to negotiate a long-term arrangement between London and Brussels is tight, and the language of Lord Frost is defiant.
“We will not be a dependent state,” he says. “We will not accept clauses that lock us in the way the European Union operates.”
While this is his first interview since the UK left the European Union, officials in Brussels are aware of his arguments. One described the observations as an “unsurprising flexing of muscles.”
Sources there say what they cannot accept is that the UK is free to undermine business on the continent in its single market.
Settlement time is running out. This does not mean that it will not happen, but there is no guarantee that it will happen.
Lord Frost said in the interview that the desire to control the country’s finances and affairs “should not be controversial.”
“This is what it means to be an independent country. This is what the British people voted for, and this is what will happen at the end of the year,” he said.
“I don’t think we’re afraid of this at all. We want the authorities back in control of our borders and that’s the most important thing.”
He said the government was “fully prepared” to trade with the European Union without a formal agreement.
In practice, this could mean export taxes and customs checks.
It is a scenario that road freight forwarders say will lead to “severe” disruption to supply chains, with border management systems not yet operational to ensure shipments are cleared going forward to the European Union.
Last week, the Road Transport Association said the UK was “sleepwalking towards disaster”.
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