BRISTOL has one of the biggest museum collections in the country with nearly two million artefacts – but most of them are hidden as there is not enough room to put them on show.

Many of the items are priceless because they are unique and could never be replaced.

It means that a value can never been put on the entire collection, although it runs into many millions of pounds.

Now Bristol City Council officials are drawing up plans to make it more accessible by creating a massive online library.

This work has already begun with an online facility for the new £26m Museum of Bristol, which is due to open in two years' time.

They also want to set up a site where people would be able to ask to see exhibits by appointment.

A large part of the collections are specimens of insects (500,000 items) and plants (500,000) and archaeological finds (500,000).

But there are also oil paintings, watercolours, etchings, prints, textiles from around the world, Eastern arts, African decorative arts, glassware, ceramics, costumes, relics dating from the Middle Ages, an Egyptian collection, social history collections and many more items.

The industrial museum, which is now closed, has many items in store, from a Concorde cockpit to a double decker bus.

Less than five per cent – about 100,000 items – are on display at any one time at the four museums that are open – the City Museum and Art Gallery, Red Lodge, Georgian House and Blaise Museum.

Paul Barnett, acting director of museums, said: "We need to improve the collection so that we have the space to show more of it and we need a system so that people understand what we have.

"Once we have achieved that, then it's up to people to decide what they want to see and when. The collection is in public ownership and therefore we want to make it as accessible to people as we possibly can."

Every item in the collection is being photographed, a task that is expected to take several years. It is hoped an online library will help families, researchers, students and visitors view exhibits at the touch of a button and go and see them.

Many artefacts have to be stored in controlled conditions so they do not deteriorate. Ancient documents, for example, would turn to dust if temperature and humidity were not carefully regulated.

Council officials realise that the collection must be properly organised because of an increasing thirst for knowledge about our past.

A good example of this is Bristol's archive at the Create Centre, which contains millions of pieces of paper that chart the city's history since its founding in 1155. The archive – which used to be based in the basement of the Council House, and went online four years ago – is now open at weekends to cope with demand.

Mr Barnett said: "There has been a big growth in people wanting to find out about their personal history – genealogy has now overtaken fishing as our most popular pastime.

"Changing lifestyles and the fact that we are growing older and have more leisure time means there is growing demand for information."

Another issue for museum staff is to cope with a collection which is constantly growing in size. This is not due to purchasing even more artefacts but a growth in photographic, film and spoken exhibits.

The new Museum of Bristol at Prince's Wharf is expected to free up some space for exhibitions and community use. But it is seen as only one part of the equation to bring the entire collection into the 21st century.

One possibility being explored is to use A and B bond warehouses in the Cumberland Basin for open storage. If they were converted, then space at the museums could be freed up to show more stored exhibits.

The council would also like to bring more travelling exhibitions to Bristol but it could only do this if there was space available.

Mr Barnett said the Banksy exhibition showed what success could be achieved. He said the museum service could play a part in helping to improve the economy by drawing people to see global exhibits that date back centuries.

Mr Barnett said: "We should be considering what is our role on the national stage because of the size and quality of our collections."

Councillors will be discussing the way forward for the museum service at a council meeting in November.

There is expected to be support for 28 recommendations that set out long-term plans for the collections.