But both sides can agree that many, if not most, of the laws passed in the 27 member states stem from EU legislation.

To mark the 50th anniversary of the Treaty of Rome on 25 March, we note here 10 things the EU has done for the ordinary citizen.

It is much easier now for Europeans to move to neighbouring states

In the old days, travellers in Europe had to put up with different currencies, regular border crossings and customs checks, and even trains of different gauges - you climbed out of a French train, walked across the border, and got into a Spanish train of a slightly different size. Now one currency, the euro, suffices for most European countries and border posts have been abandoned between the 15 countries that have implemented the Schengen accords. Holidaymakers are fully covered for any emergency hospital treatment they may need in another EU country, driving licences issued in one EU country are valid in any other, and any driver insured in one member state has at least third-party cover in the rest. If you are travelling with a tour operator, the company must have systems in place to get you home if it goes bust while you are away.

Europeans are generally free to go where they want within the EU to live or work, and some 15 million Europeans have moved across borders to exercise this right. For example, more than 300,000 people are drawing UK state pensions in other member states (mostly Spain and Ireland). Older member states have imposed temporary labour restrictions on workers from countries in Eastern Europe which joined in 2004 - but these will gradually be phased out. An EU citizen living in another EU country enjoys equal treatment with nationals of the host country in terms of welfare protection, and can stand for office in local and European Parliament elections.

The EU has standardised and strengthened workers' rights

The principle of equal pay for men and women was enshrined in the 1957 Treaty of Rome, which first established the European Community. The principle has been turned steadily into reality. A 1975 directive ensured that women paid less than men for the same job got the right of redress through the courts, and protection against dismissal. More recently EU legislation has awarded part-time employees, who are often women, the same rights as people working full-time. Discrimination on the basis of race or sexual orientation is also outlawed. And age discrimination laws which came into force in the UK and other member states in 2006 stemmed directly from legislation passed at EU level.

The EU Working Time Directive ensures that all Europeans get at least four weeks of paid holiday per year. In the US, there is no statutory minimum and many employees get only two weeks of paid annual leave. The same directive guarantees workers 11 hours rest in every 24 hours, one day of rest per week, and a rest break if the working day is longer than six hours. EU legislation also sets minimum standards for paid maternity and paternity leave throughout the EU.

Thousands of students take part in foreign exchanges ever year under the EU's Erasmus programme. In the 2003-4 academic year, 7,500 UK students spent between three and 12 months at a university in one of the other member states. The programme helps students learn foreign language, gain experience of another culture, and profit from the host country's expertise in their field of study. People who want to attend a university in another EU country can also apply to do their entire degree course there, without having to pay extra charges imposed on foreign students from outside the EU.

The EU swept away barriers to free competition in the air transport market in the 1980s and 1990s, paving the way for the emergence of budget airlines. Between 1992 and 2000 prices at the cheaper end of the market fell by 40%. At the same time, consumers benefited from a wider choice of both carriers and destinations, the number of routes linking EU member states increasing by nearly 50%.

During the 1990s, the EU broke the monopolies held by public telecoms operators. The result was a doubling of the number of fixed-line operators between 1998 and 2003, rapid introduction of new technology, and lower prices. According to the European Commission, the price of international telephone calls in the EU has fallen by 80% since 1984. The EU has now begun taking action to reduce the cost of roaming on mobile phones.

Consumers can send back a product bought anywhere in the EU if it breaks down within two years of purchase. People shopping on the internet, by telephone or mail order, can also change their mind within seven days, and cancel the contract without giving a reason. EU law prohibits misleading advertising and requires that all products put on the market are safe. Shoppers who buy goods for their own use in one EU country can take them to another EU country without paying excise duty, as long as they accompany them.

Under EU law, all ingredients used in food products must be listed. Any GM ingredients must be flagged up, as must colouring, preservatives, sweeteners and other chemical additives. Any ingredients that consumers may be allergic to, such as nuts, must be marked, even if the quantities used are very small. EU laws define the conditions food must meet to be described as organic, and ensure that a name associated with a high-quality product from a particular region, such as Parma ham, cannot be used to describe a product of lower quality, or one from a different region.

The EU is widely credited with forcing the pace on improvements to the quality of air, rivers and beaches. Member states might have done the job independently in their own time, but peer pressure upped the tempo when European ministers got together to pass laws. Measures such as the Urban Waste Water Treatment Directive have led to dramatic improvements in the rivers over the last 30 years, making possible, for example, the return of otters to the British countryside. Other legislation has greatly reduced the problem of acid rain; the UK, once the "dirty man of Europe" cut sulphur emissions by 73% between 1990 and 2002. And if 30 years ago most British beaches failed the test of the EU Bathing Water Directive, now 98% of them get the thumbs-up.