In June, proposals for a massive shake-up of the European Union are due to be presented to EU leaders.

Members of the Convention on the Future of Europe have been debating the plans for months.

So why do they matter? And what is the UK's position? BBC News Online explains the key issues.

The convention - basically a big committee - was set up to draw up a new constitution for the European Union.

The idea is that those on the convention will come up with a blueprint for the way the EU will work in the future.

Among the decisions to be made will be what powers national governments retain, and what powers are handed over to Brussels.

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.

Basically, members are trying to come up with a blueprint for the future of the EU.

They are working on proposals for an EU constitution and for new working arrangements.

The convention hopes to find ways to put the EU in touch with the people of Europe and rid it of its image as bureaucratic and irrelevant.

It is also meant to resolve some of the issues about the organisation and structure of the EU, which cause tensions and divisions between members.

The convention's proposals will then be debated by EU leaders at a summit in June.

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 14 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.

Two former prime ministers - Giuliano Amato of Italy and Belgium's Jean-Luc Dehaene - are his deputies.

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.

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.

The convention chairman has warned members that they must start making deals on the constitution if it is to meet its deadline of the EU summit in Greece in June.

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".

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 policy.

However, Mr Blair does want the EU's foreign policy role to be strengthened to increase its impact on world affairs.

He has tried to counter claims that he wants a federal superstate by stressing the importance of national parliaments.

The UK is unlikely, however, to support German and French calls for an elected president of the European Commission.

The convention will present its final report 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.

Some will seek approval for the plans in national referendums.

Unlikely. The government says the plans should be scrutinised like other EU treaties, through parliament.

It says the parliamentary system is the right place for such scrutiny.

Mr Hain has said the convention is a "tidying-up" exercise of the EU's structures, and no more important than other treaties which have been approved by parliament, such as the Maastricht Treaty which ushered in the single currency.

But the Conservatives say the convention touches on major issues of sovereignty.

Mr Heathcoat-Amory says many of the proposals would give the EU the powers of a state.

The Tories say the proposals must therefore be put to a vote by the people.