"I was shocked. It was just amazing," says 16-year-old Thomas Bielby about his fact-finding trip to London investigating public transport for young people. It wasn't just the cost - or lack of it. Young Londoners pay nothing for journeys that in his hometown of Middlesbrough would cost at least a couple of pounds of his pocket money or holiday job earnings. It was also that London teenagers complained about poor service if buses were 10 minutes late. "That's unreal," he laughs. "We are used to buses being an hour late."

It's an experience shared by Ashleigh Trevarrow, 16, from Darlington, who, like Thomas, is an active member of Bus Buddies, a group campaigning for cheaper, safer and more reliable bus services for young people in the North East. Her personal preference is to walk the two miles into town rather than stump up the £1.80 fare. For some journeys there is no option - there simply isn't a bus service. It is tiring, she admits. But is it safe to walk? "Safer than waiting at a bus stop," she reckons.

Postcode lottery

The problems are widely recognised. Public transport is one of the lead issues for the UK Youth Parliament and, around the country, young people, backed by youth forums or local youth parliaments, are campaigning for better deals for the simple but necessary activity of getting to and from education or social events. One of the big issues is the age that transport users are considered adults. In some regions, child fares end at 13, while in others half-price fares apply to all under-16s (see London boxout). And in London, young people can travel for free on buses and Tube trains up to the age of 17 if they are still in education.

But Tricia Jessiman, research coordinator at The National Youth Agency, says that cheaper fares are only part of the answer. "There are likely to be other issues, such as accessibility and safety," she says. The agency is planning a research project to find out what young people's priorities are, and whether they vary among age groups among other factors.

The importance of providing affordable public transport to young people has also been recognised in a series of studies. A Social Exclusion Unit report four years ago found 16- to 18-year-olds spend an average of £370 a year on education-related transport, and nearly half struggle to afford it. Young people in rural areas face particular difficulties. A report by the Commission for Rural Communities found they undertake longer journeys, pay higher average fares per mile, and get worse concession deals than young people in cities. Angela Harrison, chief executive of the Rural Youth Network, says there is a mixed picture across the country. She knows of some creative initiatives, such as twilight bus schemes to get young people to and from after-school activities. Other areas have little. She, too, stresses that it is not just about money, but about the existence of a service and how young people are treated. "Young people can be made to feel it is not a service that is there for them," she says.

Though affordability is not the only issue, it is a key one. The money young people save on transport costs allows them to take part in activities after school, says David Curtis, co-ordinator of Young NCB. "Remove free travel in London and young people will be prevented from attending football clubs, Scouts or whatever it is," he says.

So what prevents a nationwide concessionary scheme and why do such disparities occur across the UK? Christopher Nice, spokesman for the Confederation of Passenger Transport, which represents coach, bus and light rail industries, explains that it comes down to the individual operators. "It's all a matter of commercial choice and that often depends on historic arrangements or nearby competition," he says.

Local authorities can and do subsidise some routes, or enter into agreements with bus companies to reduce fares. But even the marketing of schemes is expensive for councils.

Julia Thomas, public transport campaigner at Transport 2000, says there is a great deal of buck-passing between local authorities and central government. The Department for Transport provides money through local transport plans, which councils can use to subsidise fare reductions for young people. But she fears there is a shortage of funding for such schemes and much of what there is goes on paying for concessionary fares for elderly and disabled people.

Passing the buck

Bus companies and councils also argue about where responsibility lies. Last month, Merseytravel, the public sector body that co-ordinates buses and trains in the Liverpool area, announced it was cutting £2.3m from its subsidy to local bus companies, saying company shareholders should fund the half-fare youth scheme.

Opponents argue that concessionary schemes for young people can put off other groups such as the elderly from using public transport. The fear is that by making travel free, young people will use buses as mobile youth clubs and annoy other users. It was a point made last month by Conservative Party members of the London Assembly, when they tried to overturn free transport for young Londoners by arguing the scheme had led to an increase in antisocial behaviour.

The London Mayor's office, which introduced free travel for under-16s in London in 2005, has denied that the measure has led to a rise in antisocial behaviour among young people. Yet market researchers Synovate have found there is at least a perception among a majority of bus drivers that antisocial behaviour has increased.

Despite such obstacles, it is worth persisting with campaigns. Young people report that when they approach councils and bus companies, their concerns are usually sympathetically met. Lizzie Seerly, 16, from Bristol, who faces a £6 return fare for her regular eight-mile journey to the town centre, recently presented a case for concessionary fares to South Gloucester Council, taking research developed by the local youth forum. The council agreed to have some sort of concessionary scheme in place by 2008, although it was dependent on funds. "The fact you are classed as an adult when you are 14 is ridiculous," she says. "Councillors have sons and daughters and they know the problems."

CONCESSIONARY FARES IN SCOTLAND

A teenager in Scotland would typically spend £1,034 a year on buses and trains, according to Transport Scotland. That makes the third-off concession to young people worth about £345 a year. It is on offer to all 16- to 18-year-olds, and to full-time volunteers up to 25.

The concession applies to bus and rail journeys. For buses, young people need a National Entitlement Card with a photograph and date of birth. For rail, a Scottish Youth Rail card is needed. Both are free.

Under the scheme, introduced this January, 15,000 cards were issued in the first few weeks. About 200,000 young people are eligible.

Transport Scotland, the agency of the Scottish Executive that set up the scheme, reimburses the travel companies, at a cost estimated at £27m to £30m a year. A spokeswoman says the subsidy combats social exclusion and encourages young people to use public transport.

YOUNG LONDONERS TRAVEL FREE

Free travel on buses and trams - that's what all Londoners under 16 and those aged 16 to 17 in full-time education receive. The free Oyster card can also be used in the evenings and weekends.

This means young people each save £350 a year, according to the Mayor's office. Transport for London says it has issued 108,000 cards to 16- and 17-year-olds in full-time education in the first three months since the scheme was extended to this age group last autumn out of the 130,000 eligible young people in this age range in the capital.

So why do it? To allow young people to continue education. It makes leisure activities accessible and reduces congestion.

The free travel policy was one of Ken Livingstone's manifesto commitments at the last London mayoral election. Polls carried out for the Mayor's office suggest eight out of 10 Londoners support the policy. An attempt by the Conservative group to scrap it was narrowly defeated in mid-February.