In October 1997, the Shadow Cabinet agreed to oppose British membership for the remainder of the 1997-2001 Parliament and for the duration of the next.
Party leader William Hague put the matter to a party-wide vote at the 1998 conference. The policy was endorsed by 84.4% of members on a turnout of just under 59%.
The policy has been reiterated in the party's 1999 European Election manifesto, and as the "Sterling Guarantee" in the party's "Common Sense Revolution" policy document.
The Conservatives oppose any public spending on the National Changeover Plan, the government's guide to preparing for the euro. Mr Hague has dubbed it the "National Handover Plan".
EXPANSION AND REFORM
Britain should be "in Europe but not run by Europe". The party supports EU expansion to the east - but believes that the institutions have "reached a fork in the road".
It proposes that Europe should not go down the road of a superstate, but that of "different nations combining in different combinations for different purposes and to a different extent".
Conservatives therefore insist that there should be Treaty 'Flexibility'.
Members would agree to the single market and the core elements of its workings - but they would "only participate in new legislative actions at a European level if they see this as in their national interest".
The Conservatives oppose giving up national vetoes for more qualified majority voting within the Council of Ministers. The party opposes the Nice Treaty on this basis.
It opposes the introduction of a EU Charter of Fundamental Rights enforceable by the European Court of Justice. The party says that this charter would inevitably overrule law-making at Westminster, and would be the first step to a European constitution.
The party proposes amending domestic law to define "reserved powers" - legislation that it says would prevent EU law from overriding the will of Parliament. Any further transfer of power from Westminster to Brussels would be subject to a referendum.
RAPID REACTION FORCE
The Conservatives oppose the creation of the Rapid Reaction Force because it says that it is effectively a European army in all but name that will operate outside of Nato.
The party's 1999 European Elections manifesto states: "The European Union does not need its own army. We oppose Labour's new policy of establishing a European defence identity outside Nato.
"Making Europe's defences answerable to the EU would threaten the very future of Nato and weaken the United States' commitment to the defence of Europe."
Former prime minister Margaret Thatcher has described the project as part of a "utopian venture of creating a single European superstate to rival America on the world stage."
COMMON AGRICULTURAL POLICY
The Cap should be reformed to encourage farmers to be more efficient by removing constraints on their production. It should aim to stimulate enterprise and making targeted payments for specific activities, whether they be environmental or social.
The priority remains cutting the bill for the taxpayer and the consumer while providing long-term sustainability policies for the countryside.
The party believes that there should also be greater national responsibility for decisions currently taken at an EU level.
COMMON FISHERIES POLICY
The Conservatives want a reform of the Common Fisheries Policy that will devolve power to national, regional and local levels and will press for national or local control to be established over UK waters.
The party suggests that this could be done through either zonal or coastal management programmes.
The party also believes that the fishing industry itself should have more of a say in fishing policy as it is made.