The number of people living in Brighton and Hove will be announced in August as part of the national estimate following the 2001 census.

The figure may not mean much to the majority of the city's population, estimated to be a buoyant 262,400.

But on this simple statistic rests an enormous amount, including the amount of grant Brighton and Hove may receive from the Government, This is also based on the proportions of very old and very young people who put strains on finances.

In Brighton, because of the number of elderly people, deaths outnumber births and the natural population is declining.

But because of people coming from elsewhere, the Office for National Statistics estimates Brighton and Hove has one of the fastest-growing populations in England and Wales.

The August figure will reveal how accurate population projections have been and it will be followed by more figures.

Next year, virtually all other figures resulting from the census will be available, including ages, jobs, and car ownership.

They will also be broken down into the new wards to be used from next year's elections, rather than the old ones.

The results of the census will also be available for the first time in small districts, called output areas, with about 250 people in each.

Brighton and Hove's demographer Louise Hulton said: "This will help everything, from local businesses deciding where to locate, to nurseries wanting to know where to set up in areas with a high density of under-fives.

"It will help community associations who are applying for funding to make their case and religious organisations to get a feel for where their congregations are strongest."

The census will also tell us something about migration and Louise said: "We will be able to see how dynamic the population really is.

"Have we been invaded by Londoners seeking a better life?

"How many of us travel out of the area to work and how many are coming in every day?

"How many of us are self-employed, unemployed or working part-time? Are we working from home more and how many of us are full-time carers, either to children or relatives?

"For those who work, is a 35-hour week the norm, or are many of us working more than 50 hours a week?

"We will be able to find out all this, and more, once the results of the census have been issued."

The statistics will also help stop misinformation being put out about Brighton and Hove.

Ms Hulton recently heard an estimate that the ethnic population of the city was 20 per cent. The census is much more likely to reveal it to be about six per cent.

It has been ten years since the last census, which means figures are out of date, even though there are other ways of checking some of them, such as school rolls and benefit claims.

Brighton and Hove also has a very mobile population, which means changes here are greater than in many cities. Some are of great interest to the city.

It is thought the number of elderly people has been declining in recent years, although it is still above the national average.

At the same time, the number of young people aged between 20 and 35 is probably rising.

This has implications for the city since this is a prime age for having children.

There have been population counts since Roman times and the Domesday Book of 1088 was the first systematic attempt in England to check numbers.

Official censuses have been taking place since 1801, following concerns, later largely unfounded, that population was outstripping resources.

The one time a census did not take place was 1941, during the Second World War.

The census is gradually becoming more sophisticated, with new questions constantly added. Recent additions have included ones on tenure and long-term illness.

The council is taking part in a pioneering project to share the information with other bodies, such as health, police, fire and ambulance authorities.

Census chiefs are also trying to take account of the two per cent of people who did not fill in their forms, knowing they largely belong to certain categories such as ethnic minorities and the elderly.

Ms Hulton herself will fall in several categories of the census. She has three young children and, as well as working for the city council, she is studying for a PhD in demography.

She is eagerly awaiting the census results as they will tell us more about the complex and intriguing city that is Brighton and Hove.

Information from the 2001 census will be on the internet.

There is a web site, www.statistics.gov.uk/census2001/ to make applications for Census in Schools packs.

Ms Hulton said: "There are resource packs for primary and secondary schools. Their purpose is to show the census is not just about counting people and households but also involves maths, history, geography and citizenship."

Another site, www.statistics.gov.uk/neighbourhood gives people the chance to find out more about the areas in which they live.

Ms Hulton said: "If you are in a community group and want to find out more about your area, or a school wanting to know how your ward compared with others in the city or the rest of England and Wales, you will find much of the information you need here.

"When the census results are finally published during the second quarter of 2003, this is where you will find them."

There has been huge interest in the results of the 1901 census which has just been released on an internet site.

But Ms Hulton added: "You will not be able to find yourself in the census results until 2101 because census data falls under the 100-year rule.

"This information will remain confidential until the next century.

"Very strict data protection protocols are being developed to ensure the confidentiality of information."