Boris Johnson said it is "epically likely" a comprehensive post-Brexit trade deal with the EU will be agreed this year.
The prime minister has long insisted that he will secure a trade deal by the end of 2020, which is when the transition period following a January 31 Brexit date ends.
Asked about securing a comprehensive deal, which the EU has suggested looks unlikely be the end of December, he told BBC Breakfast's Dan Walker: "Enormously likely, epically likely."
Pressed on the possibility of such an agreement not coming to fruition, he added: "You always have to budget for a complete lack of common sense."
Mr Johnson said the debate should not be about a new deal but "a great new partnership", as he touted the opportunities for trade outside of the EU Britain would also get.
The PM previously met with European Commission president Ursula von der Leyen to discuss the potential future deal, and she expressed her concerns that the transition period was too short to secure one.
"The EU will negotiate in good faith, in the framework of the Political Declaration, with the aim of achieving the best possible outcome," she said in a statement.
"Time however is short for such an agreement to be reached and then ratified before the end of 2020. The President made clear that there is a trade-off between any regulatory divergence and access to the EU market."
She had prior used a speech to say it was impossible for such a plan to be finished this year.
