Almost £1billion will have been spent by the end of the year on the controversial Millennium Dome at Greenwich from National Lottery funds.

Yet for a fraction of that sum, Sustrans, the cycle track-building charity, is creating a millennium project that will be of lasting benefit.

Work is well on course to build the National Cycle Network, which already has opened more than 5,000 miles all over the country and which will be doubled by 2005.

The National Lottery grant was £43.5 million but when contributions from councils, firms and other organisations are taken into account, the total cost will be around £180 million.

Part of the network is in Sussex. Slowly but surely the county is being linked up so it will be possible to cycle safely along the coast and on north-south routes.

Regional manager Mark Strong works from an office in Islingword Road, Brighton, with a folding bike under his desk and a well-used cycle route just around the corner.

He said: "We are not forcing people out of their cars. Some journeys are simply not practical by bike. But we aim to persuade people that for some journeys there is an alternative to using the car.

"If people use a bike to work once a week instead of a car, that's already a 20 per cent reduction in car usage."

Sustrans' best known route in Sussex is the Cuckoo Trail, built in co-operation with councils between Polegate and Heathfield on the site of an old railway line. Before the trail was built, getting from Hailsham to Polegate other than by car was difficult. Now it's a pleasant ten-minute bike ride down a safe track.

Already the route is being extended so it is now possible to cycle directly and safely from Polegate to Eastbourne. To the north, there are plans to route it to Mayfield and beyond.

Here it will link up with the existing Forest and Worth Ways which provide a route all the way to Crawley through a safety zone being created in East Grinstead.

There's already a cycle route between Crawley and Brighton following the line of the A23. It's not ideal but, with a few improvements, could provide a popular route to the South Coast.

Putting in the network has not been an easy ride everywhere for Sustrans. For every success, such as the new two-mile route between St Leonards and Hastings opened this year, there has been a disappointment. Rother District Council, while keen on country cycling routes, is cautious about allowing bikes along the prom at Bexhill.

A cycle route opened between Rye and Camber has been highly successful both for tourists and for getting children on a safe route to schools.

But over at Seaford there is strong opposition from some locals to cycle routes along the coast. They say more cyclists will not be welcome and so far progress has been slow.

Sustrans is opening a much-needed route from Berwick station towards Alfriston, past the tourist attraction at Drusillas Zoo. But there are problems about extending it further south along the valley.

The charity is making progress with getting a new cycle route through Peacehaven, linking it to the proposed new secondary school. But once past Saltdean, there is the vexed question of whether to put it on the Undercliff Walk or on the clifftop. West of the long-established seafront cycle track in Brighton and Hove, there are plans to route it through the new development planned at Shoreham Harbour before it continues along the seafront to Worthing and beyond.

In Chichester, there has been great progress with cycle routes including the Centurion Way along an-other old railway to Lavant.

Sustrans is keen on other tracks as well as the national network. Already a route has been created from Brighton to Lewes with only the section through the Lewes Road shopping centre missing.

It is talking to the Sussex Downs Conservation Board about creating a new route through the Newtimber area and to Brighton and Hove Council about linking the back of Hove to the seafront. New routes here could also benefit pupils at both Blatchington Mill and Hove Park Schools.

All this requires endless patience and attention to detail. Mr Strong said he has been disappointed with East Sussex County Council which has generally not been forceful in taking a lead.

By contrast, West Sussex has been brilliant.

One of the most successful collaborations with a private partner has been with BAA at Gatwick Airport. Here a route has been created right through the airport. Not many passengers use it but plenty of staff do and they are being offered discounts by the company on cycle equipment as an incentive.

In Crawley, the existing network is being extended to provide routes in the town, not only to the national network, but also to local schools and supermarkets.

Sustrans wants to see bikes considered in every major development, whether it be the King Alfred Leisure Centre at Hove or in creating safe routes to new schools.

The charity is also arranging safe routes to many stations and secure cycle parking in co-operation with Railtrack.

Mr Strong believes cycling will not only reduce car traffic but will also provide a big boost to ecologically-friendly tourism.

He said: "We want to be positive and not negative in persuading people that they can use bikes."

As the network expands to be within a few minutes' ride of millions of potential riders, the prospect for bikes become ever brighter.

Anyone wishing for more information should contact www.nationalcyclenetwork.org.uk or write to EA, Sustrans, Freepost BS7739, Bristol, BS1 4BR.