Sir Keir Starmer is meeting senior German politicians this morning as he vows to ‘turn a corner on Brexit‘ and ‘reset’ Britain’s relations with Europe.

The PM held talks with Chancellor Olaf Scholz as he eyes a new treaty with Berlin aimed at boosting business and increasing joint action on illegal migration.

He will then travel to Paris for the Paralympics opening ceremony this evening, before a breakfast meeting with French business leaders on Thursday and a summit with President Emmanuel Macron at the Elysee Palace.

Sir Keir, who once backed a second EU referendum, is expected to use his two-day visit to hail a ‘once-in-a-generation opportunity to reset our relationship with Europe’.

But Tory leadership contender Robert Jenrick this morning told Sir Keir not to ‘cede control’ in his efforts to forge closer ties with the EU.

‘I don’t want us to be undermining NATO as the principal foundation of our security and defence in Europe,’ he told Sky News.

‘And I don’t want us to lose the Brexit benefits that we should now be harnessing.’

Other senior Tories warned Sir Keir was planning to ‘reopen all the arguments’ about Brexit.

They urged voters to ‘keep a close eye on what he says and does’ in Germany due to a risk he could ‘backslide’ on the UK’s exit from the EU.

The PM met German president Frank-Walter Steinmeier at the Bellevue Palace in Berlin this morning.

Sir Keir signed the palace guestbook in the entrance hall, which had been decorated with red, white and blue flowers, before holding a private bilateral meeting with Mr Steinmeier at the start of a day of meetings in the German capital.

He is the first British PM to visit Bellevue Palace, the official residence of the German president, since David Cameron in 2015.

Sir Keir came at the invitation of Mr Steinmeier after the pair met at the Euros football in Germany earlier this year.

Since entering No10, the PM has promised a ‘reset’ of Britain’s ties with the EU, to rewite the UK’s ‘botched’ Brexit trade deal, and to strike a new UK-EU security pact.

During his trip this week, the PM is expected to say: ‘We have a once-in-a-generation opportunity to reset our relationship with Europe and strive for genuine, ambitious partnerships that deliver for the British people.

‘We must turn a corner on Brexit and fix the broken relationships left behind by the previous government.

‘That work started at the European Political Community (EPC) meeting last month and I am determined to continue it, which is why I am visiting Germany and France this week.

‘Strengthening our relationship with these countries is crucial, not only in tackling the global problem of illegal migration, but also in boosting economic growth across the continent and crucially in the UK – one of the key missions of my Government.’

The UK’s negotiation team will spend the next six months working on the treaty with Germany, aiming to agree a partnership by early 2025.

Sir Keir and Mr Scholz are also expected to discuss joint action to tackle illegal migration, including further intelligence-sharing to intercept and shut down organised immigration crime rings.

The PM will also reiterate his personal condolences to the German people following the attack in Solingen on Friday, where three people died.

While he is in Berlin, Sir Keir is also expected to meet the chief executive of Siemens Energy, Dr Christian Bruch.

In Paris, the PM’s breakfast meeting is expected to include representatives from companies including Thales and Sanofi.

Sir Keir will then meet Paralympians preparing for their competitions before meeting the French President at the Elysee Palace.

Lord David Frost, who was the UK’s chief Brexit negotiator, challenged Sir Keir’s claim he wanted to ‘turn a corner on Brexit’.

He said the PM instead wanted to ‘reopen all the arguments and to renegotiate the Trade and Cooperation Agreement, in a way that starts making us subject to EU law once again’.

‘That’s not moving on, it’s moving back,’ the Tory peer added.

Ex-Conservative MP David Jones, a former Brexit minister, told MailOnline: ‘Everyone knows that Keir Starmer did his very best to stop Brexit, even calling for a second referendum when the will of the people had already been made very clear.

‘The British people should keep a very close eye on what he says and does in Germany and hold him to account if he makes yet another attempt to backslide on Brexit.’

In his Sky News interview, Mr Jenrick added: ‘The UK is well placed to tap into the fastest growing markets and sectors of the future.

‘But you don’t do that by simply tying us to Europe and ensuring all of our regulatory framework is the same as theirs. We need to be more nimble, we need to have smarter regulation.’

The PM and Mr Scholz are ‘more or less on the same page’ about improving the UK’s relationship with Europe, a senior member of the German chancellor’s party said.

Nils Schmid, the foreign affairs spokesman for the SPD’s parliamentary group, told BBC Radio 4’s Today programme that Germany would like a deal on youth mobility.

Asked what Mr Scholz would like from the meeting, Mr Schmid said: ‘They are more or less on the same page.

‘So there is a constant push by the German government to bring the UK closer to Europe and to facilitate cooperation between Great Britain and the EU in as many fields as possible, ranging from trade to student mobility rights to defence.

‘And then, of course, there’s also the idea of not only preparing the ground for a EU-UK agreement, but also to strengthen the bilateral ties between Germany and Great Britain by concluding a bilateral friendship treaty or co-operation treaty, as is already in existence between France and the UK, the so-called Lancaster House accord.’

A youth mobility scheme was ‘a major feature of our wish list’ but ‘this is not about immigration in a general sense’, he added.

‘This is about facilitating access of youth to Great Britain for stays of limited duration, for purposes like educational programmes, youth exchange or student exchange.’

But Mr Schmid suggested it could include ‘working experience which is also of limited duration’.

Last month, at the EPC summit held at Blenheim Palace, Oxfordshire, Sir Keir said the UK will be a ‘friend and a partner ready to work’ with Europe.

He added that ‘we can only make progress on the issues that so many people care about, like illegal migration and national security, if we have the maturity and leadership to reach out a hand to our European friends’.