Multiple sources in the UK Government said that the Brexit talks are likely to be concluded by next weekend. One source said they should be resolved "one way or another" this week.
Ministers in London expressed scorn on an offer from Michel Barnier, the EU's chief negotiator, that the EU will grant British access to just 15 per cent to 18 per cent of the fish in UK sovereign waters.
A UK Government source said the offer showed how far apart the two sides are, adding: "These figures are risible, and the EU side know full well that we would never accept this.
"There seems to be a failure from the Commission to internalise the scale of change needed as we become an independent nation."
Mr Barnier was in talks with his UK counterpart Lord Frost in London on Saturday. Talks are due to continue on Sunday and into the first half of this week.
Sources made clear that "the UK team will not settle for anything less than a great deal for UK fishing communities that guarantees for the first time in nearly 50 years that we have control over our waters". They added: "If the EU don't move we are prepared to leave the transition period on Australia terms".
A source close to the negotiations added: "We hope that the EU will come with some fresh thinking because what we've seen so far doesn't cut it."
The UK Government's tough line was backed by the Scottish Fishermen Federation, which likened the EU to a school playground bully who steals other children's lunch and offers crumbs back in recompense in an article for the Telegraph's website.
UK Government sources said that - even if a deal were signed at the end of this week - it would leave just eight sitting days to pass new legislation through Parliament to enact the treaty before Parliament rises on Dec 17. A source said: "We don't have a huge amount of time."
The European Research Group of Conservative MPs has made clear that it will vote against the legislation if UK sovereignty is compromised.
In a phone call with Irish Taoiseach Micheál Martin late on Friday night, Mr Johnson "underlined his commitment to reaching a deal that respects the sovereignty of the UK", a No10 spokesman said.
Under the new Anglo-French migration deal agreed on Saturday night, France agreed to double the number of gendarmes on its beaches but continued to resist taking back UK arrivals.
Although sources insisted there was no linkage between migrants and fishing rights, they pointed to the deal as evidence of the two countries' willingness to work together post-Brexit.
"We accept this is a shared problem and recognise we can only solve it by working together," said a Government source.
Priti Patel, the Home secretary, hailed the deal as "a significant moment for our two countries, stepping up our joint action to tackle illegal migration".
She said: "Thanks to more police patrols on French beaches and enhanced intelligence sharing between our security and law enforcement agencies, we are already seeing fewer migrants leaving French beaches.
"The actions we have agreed jointly today goes further, doubling the number of police officers on the ground in France, increasing surveillance and introducing new cutting edge technology, representing a further step forward in our shared mission to make channel crossings completely unviable."
The four-point plan includes a major expansion of surveillance by drones and CCTV along the 100 miles of France's northern coastline aimed to catch migrants before they leave French soil. Radar equipment, optronic binoculars and fixed cameras will also help search the coastline quicker.
It follows a seven-fold increase in the number of migrants crossing the Channel this year with a record 8,500 reaching UK shores since January.
The increase in police operations is backed by a French pledge to disperse more migrants from the north of France to accommodation centres inland where they could apply for asylum in France or other EU countries.
Border security at ports in northern and western France will be increased to prevent smugglers shifting their illegal trafficking into lorries and other freight as the French attempt to choke off the sea routes.
The agreement builds on the joint cooperation that has already seen the proportion of crossings intercepted and prevented rise from 41 per cent in 2019 to 60 per cent in recent weeks. On Friday, the French caught 20 migrants attempting to reach England.
