Grant Shapps today hit back at Angela Merkel over her plans to force all Britons travelling to the EU to quarantine.
The Transport Secretary said that border rules are ultimately a matter for individual countries to decide.
But he risked sparking a diplomatic row as he suggested the German Chancellor was only being pushed into the move because of the bloc's slow vaccine rollout.
Mrs Merkel wants the EU to tighten its borders to stop the spread of the 'Delta' coronavirus variant which has taken hold in the UK.
Mr Shapps said he understood why Germany might be 'particularly concerned' about the variant because it 'doesn't have the same level of vaccinations as has happened in this country'.
It came as Downing Street announced that Mrs Merkel, who is due to step down later this year, will visit the UK for talks with Boris Johnson at Chequers on July 2.
A Number 10 spokesman said: 'This will be a chance to discuss a range of issues, including deepening the UK-Germany relationship and the global response to the coronavirus pandemic.'
Angela Merkel, the German Chancellor, wants all EU member states to impose quarantine on arrivals from the UK
Mrs Merkel's quarantine plans risk scuppering the Government's proposals to lift self-isolation requirements for double-jabbed Brits returning from amber list countries.
Much of Europe is on the amber list and would-be UK holidaymakers are unlikely to book a trip to the continent if they face a lengthy stay in self-isolation upon their arrival.
The exact date for the easing of the amber list rules for people who are fully vaccinated is yet to be set but August appears likely.
Told that Mrs Merkel wants all EU member states to impose quarantine rules on British travellers, Mr Shapps told Sky News: 'I understand that. Germany doesn't have the same level of vaccinations as has happened in this country so they will be particularly concerned.
'Each country will have to come to their own decision. A country like Malta which has a very high level of vaccination hasn't said the same thing and other European countries will come to their own decisions and I respect that, that is for them to do.
'But it is different in each country and largely driven by levels of vaccination that they have managed to achieve in each country.'
Mrs Merkel said yesterday: 'We have not yet managed to ensure that all 27 member states have the same entry requirements for people arriving from virus variant areas, in this case Great Britain, but in other countries also.
'With us you have to be in quarantine when you come from the UK. This is by no means the case in every European country. But I would like that.'
French President Emmanuel Macron has signalled his support for Mrs Merkel's proposals.
He said: 'We must all be vigilant because the much-talked-about Delta variant is coming, which spreads much more rapidly than the other variants and affects people who are not vaccinated or who only have had one dose.
'For me, one of the issues of discussion is to be really taking co-ordinated decisions in terms of opening of borders to third countries and on recognising vaccines because at this stage we have to limit this to the vaccines that have been approved by the European medical authority.'
But Jose Ramon Bauza, the former president of the Balearic Islands, which are being added to the green list next week, said decisions on border rules must be 'based on science' and should not be 'political'.
Asked if he believes Spain will have to agree to a harmonised approach to quarantine rules if that is what is decided by the EU, he said: 'We know that vaccination is working very well and in fact in (the) UK it's working so far.'
The joint push from Germany and France came despite Boris Johnson claiming that the growing number of double-jabbed Brits should represent a 'real opportunity' to resume more international travel.