Desperate attempts to forge a deal on the future of Europe were overshadowed last night by an astonishing demand for the voting system to reflect Polish population losses caused by the Nazi invasion in 1939.

Polish leaders said the proposed EU voting formula, based on population, disadvantaged their country because it had still to recover from the millions lost during the Second World War.

The latest intervention from Poland, regarded with Britain as the main obstacle to a deal tonight in Brussels, was regarded as a move to add to pressure on Angela Merkel, the German Chancellor, who is anxious to crown her country’s presidency of the EU with an agreement she can sell at home.

She was also under pressure, although less hostile, from Tony Blair and Gordon Brown, telling her in a joint telephone call that there could be no retreat from their demands that Britain receive a water-tight legal exemption from the Charter on Fundamental Rights, and a retention of the veto on law and order and social security.

A bluffer's guide to the EU treaty

Our correspondent hacks through the verbiage to explain what happened at the EU summit and what it means

• Patchwork deal proves Europe cannot heal its deepest wounds

BACKGROUND

• Unconstitutional

• Fresh start or revived constitution?

• Merkel’s dream; Britain’s nightmare

• Brown’s first test: how to avoid an EU constitution

• Europe divided over summit plans

Related Links

• Sarkozy gets key clause dropped

• Blair: 'I'm prepared to sink EU summit deal'

• Let’s learn from the intransigent Poles

Mr Blair told The Times that he would “walk away” unless his requests were met, and his last Cabinet meeting firmly backed that stance.

Mrs Merkel will hold separate meetings this morning with the “awkward squad” leaders of Britain, Poland and the Netherlands, which is seeking a boost in the powers of national parliaments against Brussels.

Mr Blair arrived predicting a “tough negotiation”. There would have to be “really significant change” in Britain’s “red line” areas of foreign policy, the judicial system, tax and social security, and the charter.

After last night’s dinner at which heads of government set out their stances, British officials said that not only Britain but France, the Netherlands and Poland had serious issues to resolve. “There is not much sign of movement at this stage,“ the Prime Minister’s spokesman said. “Our red lines are not a menu of options. We need to see each of them met. Tomorrow we will find out whether it is possible.”

The Polish dart was fired by Jaroslaw Kaczynski, the Prime Minister. His more emollient twin brother, Lech, the President, is representing his country at the summit. But just as Mr Brown was in constant touch with the man he is about to replace, the Polish Prime Minister was equally keen to ensure that his President gave nothing away that could embarrass him later on.

The Polish Prime Minister said the voting system hurt his country because of its war losses: “If Poland had not had to live through the years of 1939-45, Poland would today be looking at the demographics of a country of 66 million.” Its population is 38 million.

Under the proposed “double majority” system, a vote requires 55 per cent of member states and 65 per cent of EU population to succeed. Germany, with a population of 82 million, benefits most from that system, while Poland loses out. It wants to revert to the system agreed at Nice in 2000, under which it achieved almost equal voting strength with Germany.

Poland lost 22 per cent of its population during the war, 500,000 fighting men and six million civilians.

Mr Kaczynski’s outburst seems certain to damage relations with his biggest EU neighbour. He told Polish radio: “It was the Germans who inflicted unimaginable injury, terrible harm on Poland – incomprehensible crimes – and Poles like Germans, while Germans do not like Poles.”

His attack offended German politicians who hit back last night. Hans-Gert Pöttering, an ally of Mrs Merkel and President of the European Parliament, said that such comments “should no longer be made in the 21st century”.

The head of the European Commission, José Manuel Barroso, predicted before the summit that the Mr Blair would leave the talks having ceded some ground. “One thing we have to accept is that in Europe you’ve got to be reasonable and rational,”Mr Barroso said.

The science of voting

Current voting system

Gives the four big member states – Germany France, Britain and Italy – 29 votes each, only marginally more than the next biggest, Spain and Poland, which have 27. Decisions require backing of 14 out of 27 mermber states and 74 per cent of the votes.

Proposed system

Sets up a “double majority” threshold. Decisions require the backing of 15 states (55 per cent) together with countries representing 65 per cent of EU population. A safeguard measure was added to prevent three big member states from teaming up in a blocking minority. At least four countries are required for a vote to fall.

Polish propsal

Based on the square root of population. Reduces the relative muscle of bigger states, especially Germany, the biggest. Germany would get nine votes relative to Poland’s six.

How deep red are the lines?

Deep Red

“Britain would not accept a treaty that allowed the charter of fundamental rights to change UK law in any way”. Most important because of the can of worms it will open up in British law and workplaces. It is the toughest to meet because of the determination of almost every other EU nation to make the charter legally binding, (David Charter writes). Mr Blair is demanding a clear and guaranteed opt-out that names Britain as being exempt from expansionist rulings from the European Court of Justice. This is to protect Britain from parts of charter that will give enhanced rights to strike and trade union recognition, and threaten challenges at the ECJ to Britain’s social laws covering areas such as abortion.

Shocking Pink

“Britain will not agree to give up our ability to control our common law and judicial and police system” Losing on this red line would certainly lead to demands for a referendum on the grounds of a loss of sovereignty. Although it seems certain that 51 extra areas of decision-making will be moved from unanimity to qualified-majority voting, meaning they cannot be vetoed, it looks as though Britain will be offered opt-outs, just as it was when EU policymaking on immigration and asylum matters was moved to QMV.

Pale Red

“Britain would not agree to something that displaces the role of British foreign policy and our foreign minister” Britain has raised last-minute objections to the powers of the proposed EU foreign minister, surprising other nations who thought it was a done deal. But Gordon Brown stepped in to insist on this because he fears that it will be seen as a transfer of sovereignty to the EU, triggering a referendum. Britain may win some reassurances but unlikely to get a dramatic change -more of a negotiating ploy to discard for other gains.

Red Herring

“Britain will not agree to anything that moves to qualified majority voting something that can have a big say in our own tax and benefits system” There are no proposals to give the EU a big say over national tax systems. In fact, the constitution refers to tax remaining a matter for unanimous decision-making. Nor is there a proposal for harmonising EU welfare systems, which was discussed at the time of the constitution but dropped.

Overlooked Red Line?

The Single Legal Personality for the EU, which will give the EU treaty signing powers, arguably a shift of power to Brussels, is another change that Mr Blair has not set as a red line but which critics say involve a significant transfer of power

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