Jacob Rees-Mogg (right) is as devout a Brexiteer as you will find on the backbenches of the Conservative Party | Dan Kitwood/Getty Images Brexit Files Insight Jacob Rees-Mogg looms over Brexit talks Theresa May faces a test on her ECJ red line, with a hard Brexiteer said to be waiting in the wings.

In its bid to convince the EU that the rigid "separation first, trade second" approach to the Brexit talks makes no sense, the U.K. is bombarding its negotiating partners this week with a series of five papers laying out the British position on a variety of issues.

Crucially, most of them are about things the EU doesn't want to talk about yet.

Whether this is a belated attempt by Brexit Secretary David Davis to ignite the "row of the summer" over the sequence of the talks or not, something that could significantly kick on that timetable is the publication on Wednesday of the U.K.'s vision for how the adjudicatory role of the European Court of Justice can be replaced post Brexit.

Theresa May has made shedding the influence of the EU's highest court in Luxembourg a red line in the talks, but its involvement in countless Brexit issues makes it a massive sticking point.

Producing a serious, workable alternative proposal for a mechanism to oversee trade, security and the rights of EU citizens in the U.K. after Brexit could yet help to unclog talks.

But this is easier said than done for the British government.

Enter Jacob Rees-Mogg — as devout a Brexiteer as you will find on the backbenches of the Conservative Party — whose Tory leadership prospects have filled British column inches in the arid summer months for political news.

The MP’s wit, self-deprecation and mastery of media has caught attention and earned the parliamentarian, once dubbed the “honorable member for the early 20th century,” a following (one poll of Tory members last month put him third favorite behind David Davis and Boris Johnson).

As Tories soul-search after a disastrous election, some wonder if this right-wing social media sensation is the antidote to opposition Labour leader Jeremy Corbyn, who has harnessed the youth vote with a savvy online cult campaign.

While few Tory MPs consider Rees-Mogg a serious prospect (Rees-Mogg insists he wants to be a servant not master of his party) he is being egged on by some in the hard Brexit wing of the party. And that may make it harder to carve out an ECJ compromise, such as the suggestion that the U.K. could link up with the European Free Trade Association's court as an alternative to the ECJ.

"The big difficulty is that the EFTA court takes its lead from the ECJ and while its rulings are technically advisory, in practice they take direct effect in the countries concerned. That would be unacceptable," Rees-Mogg told the Times.

The hard Brexit wing of the party has been supportive of Theresa May since her disastrous general election result. They fear the distraction of a leadership race could put Brexit at risk. But Rees-Mogg leadership headlines (along with other more obvious candidates in the Cabinet) are a helpful reminder that there are Tory MPs waiting in the wings if May deviates from a hard Brexit path.

The loyalty of Brexiteer Tory MPs will be tested this week when they see what the government's ECJ red line looks like in practice.

This insight is from POLITICO's Brexit Files newsletter, a daily afternoon digest of the best coverage and analysis of Britain’s decision to leave the EU. Read today’s edition or subscribe here.