Cameron has '27 nuts to crack' to successfully renegotiate EU membership

The Prime Minister conceded that he was "not met with a wall of love" when he joined forces with his counterparts in the Latvian capital, Riga, at the weekend. Who will he meet on his tour and what sort of reception can he expect to find?

GERMANY
Founding member (as West Germany)
Head of government: Angela Merkel (chancellor since 2005, leader of the centre-right Christian Democratic Union)
Government: grand coalition of right and left-wing parties

The most influential of all the 28 member states. Mrs Merkel must be on board if Mr Cameron is to stand a chance of securing a deal.

She says she is keen for the UK not to leave and willing to look at "abuse" of freedom of movement - but will not question the principle "in any way".

Finance Minister Wolfgang Schauble has not ruled out at least the promise of future treaty change and said there is "huge interest" in keeping Britain in.

ITALY
Founding member
Head of government: Matteo Renzi (prime minister since 2014, leader of centre-left Democratic Party)
Government: Grand coalition of right and left-wing parties

Mr Cameron has the backing of Mr Renzi for efforts to cut Brussels bureaucracy and the Italian premier says it is "essential and crucial" that Britain does not leave the EU.

But he has signalled that the PM's desire for more fundamental treaty changes, such as restrictions on the right to claim benefits overseas, are not a priority.

"Clearly there is no great Europe without the presence of the United Kingdom, without David Cameron and the British people," he said last year.

SPAIN
Joined: 1986
Head of government: Mariano Rajoy (prime minister since 2011 and leader of the conservative People's Party)
Government: People's Party majority government

As with those of many other countries across the continent, the Spanish government has too many pressing domestic concerns - not least continued struggles to revive their economies - to have given much attention to the UK's demands.

Mr Rajoy, who backs more not less European integration, faces a general election this year, with anti-austerity parties threatening to transform Spain's political landscape.

FRANCE
Founding member
Head of government: Francois Hollande (Socialist president since 2012)
Government: centre-left coalition

Mr Hollande has indicated an openness to seeking a new deal but warned it is up to Mr Cameron to do the hard work.

"We ask for nothing. Europe is not concerned by a vote," he said.

France and Germany have already drawn up joint proposals aimed at avoiding the need to reopen the EU's treaties in order to reform the eurozone.

POLAND
Joined: 2004
Head of government: Ewa Kopacz (prime minister since 2014 and leader of liberal-conservative party Civic Platform)
Government: Coalition of Civic Platform and Polish People's Party

ROMANIA
Joined: 2007
Head of government: Victor Ponta (prime minister since 2012 and leader of the Romanian Social Democratic Party)
Government: Grand coalition of parties

CZECH REPUBLIC
Joined: 2004
Head of government: Bohuslav Sobotka (president since 2014, chairman of the Czech Social Democratic Party - CSSD)
Government: centre-left coalition

BULGARIA
Joined: 2007
Head of government: Boyko Borisov (prime minister since 2014, leader of centre-right GERB - Citizens for European Development of Bulgaria)
Government: centre-right coalition

SLOVAKIA
Joined: 2004
Head of government: Robert Fico (prime minister since 2012 and leader of the left-of-centre Direction - Social Democracy)
Government: A majority Direction government

SLOVENIA
Joined: 2004
Head of government: Miro Cerar (prime minister since 2014 and leader of the centrist Modern Centre Party)
Government: Grand coalition of three parties

CROATIA
Joined: 2013
Head of government: Zoran Milanovic (prime minister since 2011, leader of the centre-left Social Democratic Party)
Government: centre-left coalition

ESTONIA
Joined: 2004
Head of government: Taavi Roivas (prime minister since 2014, leader of the centre-right/liberal Estonian Reform Party)
Government: Grand coalition of right and left-wing parties

LATVIA
Joined: 2004
Head of government: Laimdota Straujuma (prime minister since 2014, representing the liberal-conservative Unity party)
Government: Grand coalition of parties

LITHUANIA
Joined: 2004
Head of government: Algirdas Butkevicius (prime minister since 2012, leader of the centre-left Social Democratic Party of Lithuania)
Government: Coalition of centre-left parties

While he may have allies among the newer EU members from the former communist bloc, Mr Cameron faces a very tough battle over one of his key demands: restricting benefits for migrant workers coming to the UK.

A succession of senior figures in Poland - which has just elected a hardline right-wing Eurosceptic MEP as president whose party hopes to seize power in an autumn general election - have condemned curbs as "discriminatory" and pledged to block them Polish PM Ewa Kopacz said recently that the EU should consider "the problems facing each of its member nations."

One Czech minister made a stinging riposte - posting a picture to Twitter of Czech pilots serving in the RAF during the Second World War with the caption: "These Czechs 'worked' in the #UK for less than four years. No benefits for them?"

Romanian officials are reported however to have indicated that there is scope to negotiate on the issue.

Estonian prime minister Taavi Roivas said he is "open to discussion" but warned that he would oppose any attempt to roll back the free movement of labour within the EU.

THE NETHERLANDS
Founding member
Head of government: Mark Rutte (prime minister since 2010, leader of the conservative-liberal People's Party for Freedom and Democracy)
Government: Coalition of the People's Party and the Labour party

Mr Rutte is a potentially very strong ally who sings from the same hymn sheet over issues such as the cost of the EU, red tape and the need to return decisions to national parliaments - though is very much someone seeking to reform from within, not seek opt-outs.

BELGIUM
Founding member
Head of government: Charles Michel (prime minister since 2014, former leader of liberal Reformist Movement)
Government: centre-right coalition of various parties

The home of the European Commission has historically been one of the most staunchly federalist EU members - though the inclusion in its latest coalition government of a centre-right "Euro realist" Flemish nationalist party has seen a slight shift in favour of empowering national parliaments, another of the likely areas for Mr Cameron to seek changes.

GREECE
Joined: 1981
Head of government: Alexis Tsipras (prime minister since 2015, leader of left-wing Syriza)
Government: coalition of Syriza with minority conservative party Independent Greeks

It is not so much the country's attitude towards Mr Cameron's desired reforms that could have an impact as the success or otherwise of the debt-ridden nation's negotiations with its creditors.

If Athens was to be forced out of the single currency - the much-feared "Grexit" - the ensuing crisis would divert all the attention of EU leaders and push British concerns on to the back-burner.

PORTUGAL
Joined: 1986
Head of government: Pedro Passos Coelho (prime minister since 2011 and leader of the liberal/centre-right Portuguese Social Democratic Party)
Government: Centre-right coalition of the Social Democratic Party and the People's Party

Mr Passos Coelho could be an ally but faces a struggle to see off a socialist challenge in an election this year.

He has drawn inspiration from Mr Cameron having "defeated the odds" to remain in power on May 7.

HUNGARY
Joined: 2004
Head of government: Viktor Orban (prime minister since 2010, leader of right-wing Fidesz party)
Government: A majority Fidesz government

There has already been one alliance between Mr Cameron and his counterpart Mr Orban over Europe - albeit an ill-starred one as they found themselves alone in seeking to block the election of Jean-Claude Juncker as Commission president.

Fertile common ground with the mildly-eurosceptic administration in Budapest could include the repatriation of powers from Brussels.

SWEDEN
Joined: 1995
Head of government: Stefan Lofven (prime minister since 2014 and leader of the Swedish Social Democrats since 2012)
Government: Coalition of left-of-centre parties

Mr Cameron lost an important ally when Fredrik Reinfeldt's centre-right administration was booted out last year and replaced by a fragile socialist-led government, with a far-right anti-immigrant outfit holding the balance of power.

AUSTRIA
Joined: 1995
Head of government: Werner Faymann (chancellor since 2008, chairman of centre-left Social Democratic Party)
Government: grand coalition of Social Democratic Party (SPO) and centre-right Austrian People's Party (OVP)

Relations with Vienna have been strained by a serious diplomatic spat over the EU's decision to approve a state subsidy for a new £16 billion nuclear power station at Hinkley Point in Somerset.

Nuclear-free Austria is poised to open a legal challenge against the decision, three months after Mr Cameron clashed with Chancellor Werner Faymann at a summit in February over the issue.

But Foreign Minister Sebastian Kurz has suggested there are "many areas where you can make significant progress for the EU without treaty change" and that people should not reject reform ideas "just because they come from Britain".

DENMARK
Joined: 1973
Head of government: Helle Thorning-Schmidt (prime minister since 2011, leader of the Social Democrats)
Government: Minority centre-left coalition

Like the UK, Denmark has chosen to remain outside the single currency and enjoys a series of national opt-outs from aspects of the EU.

It was due to be Mr Cameron's port of call but talks in Copenhagen will now await the result of a snap general election called for June 18 by centre-left coalition leader Mrs Thorning-Schmidt, the wife of Labour MP Stephen Kinnock.

Her centre-right rivals are ahead in opinion polls.

FINLAND
Joined: 1995
Head of government: Cai-Goran Alexander Stubb (prime minister since 2014, leader of the centre-right/liberal National Coalition Party)
Government: Grand coalition of right and left-wing parties

Mr Stubb expressed confidence at the weekend that a deal could be found which would satisfy all sides.

"Finland is very much in favour of the pro-reform agenda that David Cameron drives. We believe that there are issues that can be discussed with Britain," he said at the Riga summit.

IRELAND
Joined: 1973
Head of government: Enda Kenny (prime minister since 2011, leader of centre-right Fine Gael party)
Government: Coalition of Fine Gael and Labour

Such are the concerns in Dublin about the potentially severe ramifications of its closest neighbour and trading partner leaving the EU that Taoiseach Enda Kenny has set up a special unit to examine the issue.

The two countries are often very close allies in Brussels and Mr Kenny is due to have talks with Mr Cameron early next month.

CYPRUS AND MALTA

Cyprus
Joined: 2004
Head of government: Nicos Anastasiades (president since 2013, former leader of centre-right Democratic Rally)
Government: centre-right coalition

Malta
Joined: 2004
Head of government: Joseph Muscat (prime minister since 2013, leader of the Maltese Labour party)
Government: majority Labour government

The tiny island nations - both members of the Commonwealth with deep ties to the UK - will be very keen to avoid a No vote in the referendum, in which their citizens living here will be eligible to vote.

LUXEMBOURG
Founding member
Head of government: Xavier Bettel (prime minister since 2013, leader of the centre-right Democratic Party of Luxembourg)
Government: Grand coalition of right and left parties

Relations could be less than cordial if it maintains its support for Austria's bid to block subsidies for the UK's nuclear power.

As the man who helped legalise same-sex marriage in the UK however, Mr Cameron may enjoy some respect from the tiny country's first openly-gay leader Mr Bettel who wed his partner earlier this month.