The EU has already launched legal proceedings against Britain over a unilateral six-month delay to imposing customs controls on goods arriving in Northern Ireland from Britain.
Mark Simpson, an expert on financial services at the law firm Baker & McKenzie, agreed that by the metric of job losses, London did not need to panic yet.
"Today is more than a transition. Today is an opportunity to rejuvenate our transatlantic relationship, which has greatly suffered in the last four years. In these years, the world has grown more complex, less stable and less predictable".
Barnier indicated he planned to back, as before his departure to Brussels, the right-wing The Republicans (LR) rather than Macron's The Republic on the Move (LREM).
The UK wants to gradually curb EU access to its fishing waters over three years, while the bloc is proposing six years, to give its fishing industry longer to adjust.
SPDR Gold Trust the world's largest gold-backed exchange-traded fund, said its holdings fell 0.20% to 1,167.53 tonnes on Tuesday from 1,169.86 tonnes on Monday.
The dollar index recovered on the day and was last up 0.2pc just short of 90, but remained on track for a fall of 1pc over the week. It had reached its lowest in more than two years at 89.723 on Thursday.
The European Parliament has demanded that it see the text of any accord by Sunday at the latest, and the UK government says it will not allow talks to go beyond December 31.
While Barnier said the sides were striving at an agreement, he said the 27-nation bloc would not sign a deal that would undercut its cherished single market of 450 million consumers.
The EU sources said that any agreement that could emerge would produce a "differentiated" system on fishing quotas, but did not expect that to happen by Friday.
An EU official, who declined to be named, said disagreements over fisheries were not yet resolved, and many more minor issues still required "polishing".
The pound is benefiting from an improvement in the narrative on the chances of a Brexit trade deal this week, almost a year after Britain formally left the European Union.
"The prime minister will leave no stone unturned in this process, but he is absolutely clear: any agreement must be fair and respect the fundamental position that the UK will be a sovereign nation in three weeks' time," the source said.
Barnier and Frost will resume face-to-face talks later on Monday before reporting back to their respective bosses, EU chief Ursula von der Leyen and UK Prime Minister Boris Johnson.