Angela Merkel arrives in London today for a high-profile visit which David Cameron hopes will bolster his bid to negotiate a better deal for the UK in the European Union.
The German chancellor, whose support will be pivotal to the Prime Minister's reform efforts, is being granted the full red carpet welcome - including addressing Parliament and meeting the Queen.
She has been tipped to indicate her support for Britain staying in the EU and offer Mr Cameron backing over issues such as protecting non-eurozone countries from being outvoted on single market issues.
An opt-out for the NHS from the working time directive is reported to be among measures Berlin is prepared to signal it will accept in the face of eurosceptic demands to repatriate powers.
Even limited support would help bolster the PM's search for other allies, given Germany's influence in the EU, but is unlikely to calm restive Tory backbenchers who favour exiting Brussels altogether.
Mr Cameron says renegotiated terms of membership would be put to a straight in/out referendum on Britain's continued membership of the EU by 2017 if he secures a second term as prime minister.
The visit comes less than three months before European elections in which the UK Independence Party is expected to perform strongly enough to relegate the Tories to third place and even win.
The lavish programme for the recently re-elected German leader is in stark contrast to that recently afforded French president Francois Hollande, who has made clear EU reform is not a priority.
Mrs Merkel has been granted a rare chance to address MPs and peers in the Royal Gallery of the House of Lords, and will then have lunch with Mr Cameron at Number 10 before her audience with the Queen.
Last month's Anglo-French summit was held on an RAF base, with the two leaders giving a short press conference in a hangar before visiting a nearby pub for lunch.
The 90-minute lunchtime talks with Mrs Merkel are expected to address tensions over the filling of key EU posts - including the replacement of Jose Manuel Barroso as European Commission president.
Mrs Merkel's party is backing federalist former Luxembourg premier Jean-Claude Juncker for the role - while Downing Street wants someone more supportive of Mr Cameron's desired reforms.
The Prime Minister is also expected to seek her support for placing the next UK commissioner into one of the important economic roles overseeing trade or the single market.
Developments in Ukraine and progress towards a trade deal between the EU and the United States are also on the agenda.
Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband are also due to hold talks with the German chancellor.
Labour's Europe spokesman in the Lords was slapped down after saying the UK should not permanently rule out joining the euro and calling for the party to adopt a less "defensive" stance on the EU.
Lord Liddle told The Guardian it was "just ludicrous" for politicians to suggest Britain could cut itself off from the single currency altogether in case it emerged stronger from its present crisis.
But a party spokesman insisted: "It will not happen".
Shadow chancellor Ed Balls has previously declared there is "no possibility of the euro being joined by a British government at any time in my lifetime" while Mr Miliband has said it is "very unlikely".
Lord Liddle, a former adviser to Tony Blair and the EU Commission president said:"The attitude of mind of people that we can cut ourselves off from this is just ludicrous.
"We are an integral part of an integrated European economy. So, in time, if the euro sorts itself out surely the logic is: why should we hang back from that?"
"If the euro does overcome its problems it is arguable that Britain has a flexible enough economy to be able to survive within the euro's constraints. One shouldn't close one's mind on ideological grounds to the possibility of joining."
But a Labour spokesman said: "Labour in government made the right decision not to join the euro a decade ago. It's a decision which has stood the test of time.
"Ed Miliband and Ed Balls have both said that joining the euro would not happen in their political lifetime. It will not happen."
Lord Liddle said his party was "defensive" about Europe.
"We could do much more to demonstrate how European solutions are complementary to what we want to do at home in tackling all these challenges we face."
An eve-of-visit poll produced a concerning finding for Mr Cameron: asked to say which of the two was the better politician, four times as many Conservatives picked Mrs Merkel (28% to 7%).
Overall UK voters rate their PM marginally better than his German counterpart (11% to 10%) but only because five times as many Labour voters who expressed a preference backed him (by 10% to 2%).
They were considered equally good as each other by 41% of voters in the YouGov survey.
Mrs Merkel - mentioned twice as often by respondents than Adolf Hitler when asked to say the first word that came to mind about Germany - was viewed positively by 44% to 11%.
The poll found Germany was overwhelmingly the major European country with which British voters think the UK should maintain good relations - 45% picking it from a list.
France came a poor second with 11% - just ahead of Russia's 9%.
Despite more than one in four (26%) agreeing that their perception is still clouded by the Second World War - general perceptions of Germany were positive by 59% to just 9%.
YouGov surveyed 1,936 adults between February 24-25.