Boris Johnson will take personal charge of the next phase of Brexit negotiations, Downing Street announced as Ireland claimed the EU has a “stronger team” than the UK.

The prime minister will oversee a new “task force Europe” team based in No.10, a “a small and agile unit” of about 40 people headed by his new chief negotiator David Frost.

Frost will now be Michel Barnier’s opposite number during negotiations, the role previously carried out by Brexit secretary Stephen Barclay, whose Department for Exiting the EU (DExEU) will cease to exist when the UK leaves on Friday night at 11pm.

Johnson’s official spokesperson revealed the details as Irish premier Leo Varadkar claimed the EU would enter talks on a long-term future relationship in a stronger position than the UK.

As he met EU chief negotiator Barnier in Dublin, Varadkar told the BBC: “The European Union is a union of 27 member states. The UK is only one country. And we have a population and a market of 450m people.

“The UK, it’s about 60 [million]. So if these were two teams up against each other playing football, who do you think has the stronger team?”

Varadkar also suggested a post-Brexit UK may have to trade fishing rights in exchange for UK financial services to have better EU market access. Downing Street appeared open towards this approach.

The Irish taoiseach said: “The United Kingdom has a very strong position on fisheries. The UK has a lot of waters, and a lot of fish is taken out of your waters by boats from other countries.”

He went on: “An area where you’re in a very weak position is one of the most valuable parts of the British economy which is financial services. It’s such a crucial part of the of the British economy.

“So, you know, you may have to make concessions in areas like fishing in order for us to get concessions from us in areas like financial services.”

But he also pointed out: “Bear in mind 70% of the fish you sell, you sell into Europe. So unless British people are going to start eating an awful lot more fish, you have a problem there.”

Responding, Johnson’s spokesperson said: “The key issue from our point of view is we will have full control of our fishing waters.”

Asked if this would include access for European fishing boats, he replied: “It will be for the UK to determine for the best interests of the United Kingdom who fishes in its waters.”

It is currently unclear whether Barclay will be out of a job come Friday night evening despite having led successful negotiations on the withdrawal agreement, although an announcement on his future is expected soon.

Frost, who is seen in Whitehall as having a keen eye for Brexit detail, will be supported by deputies from the Foreign Office and Treasury.

They will also work across Whitehall in specific policy areas, while the Foreign Office will regain responsibility for diplomatic engagement related to Brexit.

Michael Gove will take charge of implementing the withdrawal agreement which comes into force on Friday, and getting ready for the end of the transition period in December.

Britain, meanwhile, will no longer sit with the EU at international meetings, and will engage with Brussels as it does with other countries around the world.

“We will speak at our own right in meetings rather than letting the EU speak for us,” the spokesperson said.

And in Brussels UKRep will be replaced by a new organisation called the UK mission to the European Union (UKmis), in line with other countries.

Tim Barrow will become the UK’s ambassador to the EU.