The Prime Minister alarmed Brexiteers this week by warning MPs that her Brexit timetable may slip as the complexity of the task emerges.
Any extension would delay the UK’s ability to sign trade deals with the rest of the world which has prompted the International Trade Secretary to say he would refuse to back the extension of the current 21-month-long period beyond December 31, 2020.
Dr Fox said: “I wouldn’t like to see that, nor would I support an extension.
“The public would see an extension beyond 2020 as too slow, given that it would be a number of years since the referendum”.
Some MPs warned that as the full details of the UK-EU trade deal won’t be concluded until close to the end of the transition period it will be extended to avoid a cliff-edge for businesses.
Mrs May hinted to a committee of MPs on Tuesday that the end of the transition period could slip because of new border systems being implemented.
She said: “Sometimes the timetables that have originally been set are not the timetables that are necessary when you actually start to look at the detail”.
Dr Fox also refused to commit to being able to implement a single new trade deal when the UK leaves the bloc on January 1, 2021.
Around 40 “rollover” agreements with countries the UK has already established trade deals with will be in place.
A Downing Street spokesman said: “We’ve been clear on the implementation being a fixed time-limited period – that remains the case.”
Dr Fox revealed 14 working groups have been set up in order to push through the trade deals, which can be fully completed after the UK’s transition period ends in December 2020.
With one year to go until the formal Brexit date, Dr Fox hit back at gloomy forecasts for the UK’s future, stating a number of trade deals ready to go at the end of transition would depend on negotiations but as many as 70 countries have engaged with the UK about future relationships.
He also offered a welcome boost to Brexiteers concerned about the transitional agreement, insisting it is unlikely to be extended, therefore, allowing the UK to press on with its future.
Speaking to BBC Radio 4’s Today programme, Dr Fox said: “We will have arrangements that we will be able to roll over from the European Union’s agreements, we hope to have around 40 of those.
“We hope we will have all of those in place by the time we go.
“There are about 70 countries and 40 agreements. We hope all of those ones will be ready because they are extensions of what we have at the moment.
“Of course, we require the agreement of the countries involved. We have spoken to all 70 countries involved. They have all given agreement that they’d like to see that in place.”
While Britain is not able to officially complete trade agreements throughout the transition period, Dr Fox said he wanted the UK to take advantage of “being able to negotiate beyond the European Union’s borders”.