The UK's role in Europe is back in the political headlines.
The government is facing calls for a referendum on proposals for a massive shake-up of the European Union.
At the same time, it is preparing to unveil its decision on whether to call a poll on joining the euro - the single currency of the European Union.
BBC News Online explains why Europe is on the political agenda again.
What are the issues being debated?
There are two big European issues on the agenda at the moment.
One is the government's decision on whether the UK is ready to join the euro.
The other is about the Convention on the Future of Europe, which has drawn up proposals for an EU constitution and changes to the way the EU works.
Are the two issues linked?
They are linked in the sense that both are about the UK's relationship with the European Union.
Some believe the row over the convention and how that goes down in the country, will make it easier, or harder, for the government to win a referendum on the euro.
But essentially the two debates can be seen as separate.
What is the Convention on the Future of Europe?
The convention - basically a big committee - was set up to draw up a new constitution for the European Union once it expands to 25 members next year.
It started work a year ago.
Those on the convention have now come up with a draft blueprint for the way the EU will work in the future.
The plans make recommendations about what powers national governments retain, and what powers are handed over to Brussels.
The convention has also proposed an EU president, an elected European Commission president, an elected foreign minister, a legally-binding charter of rights, backing for a common foreign policy, a legal "personality" for the EU, more co-operation on social security, justice and home affairs.
Why did it come about?
The European Union is changing. Many of its structures were created to manage a union of six states - soon the EU will have 25 states.
EU leaders agreed in 2000 that a debate was needed about how the union should develop.
Chaired by Valery Giscard d'Estaing
Holding year-long discussions
Aims to simplify treaties
Trying to decide balance of power between Brussels and governments
So it has nothing to do with the euro currency?
Nothing at all. Its aim is purely to examine how the EU should work in the future.
Why is it in the headlines now?
The convention published its draft plans at the end of May and they will be debated by EU leaders in June.
And the Tories have seized on that to demand a referendum - separate to any referendum on the euro currency - on the proposals.
They say they have huge constitutional implications for the UK, with more power taken away from government and parliament.
They argue, therefore, that the plans be put to the people in a vote as some other countries will do.
The call has been backed by some Labour MPs and some newspapers.
What does the government say to that?
Ministers have rejected calls for a referendum on the convention's proposals.
They have also accused the press of "hysteria", pointing out that nothing has yet been decided.
They say the final proposals will be debated by EU leaders - and insist that they will block anything unfavourable to the UK.
Why won't the government hold a referendum?
Ministers say the convention represents a "tidying up" exercise of the way the EU works.
They say any treaty agreed out of the proposals will be no different to those previously agreed in Parliament - without referendums.
But a referendum on the euro currency would be held?
Yes. The government is committed to a referendum on that issue.
Ministers are currently wading through the Treasury's analysis of whether the UK should join the currency.
A decision will be announced on 9 June.
If the decision is positive, which seems unlikely, a referendum would be held on that.
Why back a referendum on the euro, but not on the future of the EU?
The government says the two issues are not comparable.
Joining the euro - and scrapping the pound - would be, they say, a massive constitutional step and therefore must be approved by the people.
They insist, however, that the EU constitution and any changes to the way the EU works will not be as significant.
They say they will not affect the UK's sovereignty.
The changes would have to be agreed unanimously by EU leaders - meaning Tony Blair has a veto on undesirable proposals, they argue.
Who sits on the convention?
The convention is made up of representatives of EU states and parliaments, the European Commission, the European Parliament and the 13 candidate countries hoping to join the current 15 members of the EU.
The UK Government is represented by Wales Secretary Peter Hain. The UK parliament is represented by Tory MP David Heathcoat-Amory and Labour MP Gisela Stuart.
The convention is chaired by former French President Valery Giscard d'Estaing.
What exactly is the convention discussing?
Four main areas were laid out at the Laeken summit in 2001:
How to divide responsibilities between the EU and the member states
Simplification of European treaties
The status of the European Charter for Fundamental Rights - which currently has no legal force
The role of national parliaments within the European Union
The convention is also looking at the future of the European Commission, how the EU must adapt to cater for 25 members and make foreign policy work more effectively.
Are members in the convention in general agreement?
No. The convention includes those who want the EU to be run like a federal state, while others are fervently anti-federal.
Some smaller countries are concerned they are being cut out of key decisions.
What are the main sticking points?
Some on the convention fear that the new EU constitution will clear the way for a European "superstate", with member states having less power to veto decisions.
They want power to stay with national governments, through the council of ministers.
The role of the European Commission is another area of disagreement. Federalists want the commission to become much more powerful, an idea opposed by anti-federalists.
There is also concern among smaller countries that they are being cut out of key decisions.
They oppose plans for a powerful EU president and "inner cabinet".
Where does the UK stand?
Tony Blair's government backs calls for a powerful European Union president to replace the current system where the presidency rotates between member states every six months.
The plan is for a "team presidency" where smaller states would be represented.
The prime minister has also backed calls for more decisions to be made by majority voting, removing the power of countries to veto many decisions.
But he says the power of veto must remain for key areas like taxation and foreign and defence policy.
The prime minister also succeeded in getting the word "federal" dropped from the final draft of the constitution.
And as the plans must be agreed unanimously, ministers say there is no chance of the UK adopting anything seen as unfavourable to Britain.
They say they will fight plans for cross-border social security policy and any moves which would mean changes to UK domestic law.
However, Mr Blair does want the EU's foreign policy role to be strengthened to increase its impact on world affairs.
What happens next?
The convention is due to present its final report to the summit in Greece in June 2003. Then proposals for a new treaty will be put forward.
They will be discussed by EU leaders and agreed as a new treaty.
The treaty will then need to be approved in member states.
So the row will die away soon?
Highly unlikely. The calls for a referendum are gathering a head of steam at Westminster.
And they are unlikely to dissipate once the draft proposals are released.
The Tories clearly feel they are tapping into public disquiet about the convention.
Indeed, the debate will go on until a new treaty is agreed.
And it is unlikely to fade away even then.