The EU's Brexit negotiator has warned the UK that there will be a price for leaving the union.
Michel Barnier said he would never blackmail Theresa May but that he saw the process as a chance to "teach people" what it means to leave the EU.
Speaking at a conference in Italy at the weekend, he said Brexit wasn't meant to punish the UK but that it would be "an educational process" for it.
"There are extremely serious consequences of leaving the single market and it hasn't been explained to the British people. We intend to teach people... what leaving the single market means," Bernier told delegates.
He also touched on a few sticking points for the EU that are stopping them from progressing in talks, such as the UK needing to honour its promise to pay 14% of the EU budget until 2020.
Tensions continue to be high between the remaining EU countries and the UK, with Brexit Secretary David Davis responding to Barnier's comments by saying it would not be forced into a divorce bill deal.
This has been supported by other senior ministers in the UK government. International Trade Secretary Liam Fox said the country refused to be blackmailed into doing a financial deal to open discussions on trade.
The UK has also been criticised for the slow progress being made on three key issues that could make or break the deal, including financial consequences, the Irish border and citizens' rights.
Speaking on the Andrew Marr Show, Davis said the European Commission was at risk of making itself look "silly" by claiming that no progress had been made.
"We're going through [the bill] line by line, and they're finding it difficult because we've got good lawyers... He wants to put pressure on us, which is why the stance this week in the press conference. Bluntly, I think it looked a bit silly, because plainly there were things that we've achieved," he said.
After a summer break, Parliament will return tomorrow (September 5) and the Prime Minister Theresa May could face a tough first week.
Henry VII powers?
The Great Repeal Bill, which aims to replace European laws, is a point of contention for some Conservative MPs.
May and Davis have already warned their party not to obstruct the bill or they could give further support to opposition leader Jeremy Corbyn. This has reportedly rubbed some MPs up the wrong way, insisting that they have legitimate concerns about the bill.
One of the key concerns about the Repeal Bill is that it would allow so-called "Henry VIII powers", meaning ministers can change primary legislation using secondary legislation without parliament's intervention.
More than a year after the Brexit vote, the markets are still wavering as the two sides fail to reach an agreement on many key issues. This has impacted the pound significantly but financial investors will be bolstered by the bounce in employment and the success of the FTSE 100.
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