That's it: I'm boycotting Boris Bikes. Until, that is, Transport for London gives me back the phenomenally punitive £80 they've charged me for going over the free half-hour period on a few journeys.

I only need the bike for 10 minutes in the mornings - from Waterloo to Westminster. But I ended up having to hold on to it for hours, clumsily propped against the wall in my office, because there were no free spaces in docking stations in a mile's radius to where I work. I had to keep popping out throughout the mornings to seek out a free space, my money and, sadly, my time wasted.

I know: I sound like a right miserable git. The new London Cycle Hire scheme, approaching its first anniversary, is great for the environment and people's health.

But it's because I think the scheme is such a good idea and really want it to succeed that I'm here complaining, agitating for improvements from Transport for London. And I'm not the only one who should be grumpy: 15,000 users over the past year have been erroneously charged sometimes astronomical sums.

Docking stations next to large commuter stations are regularly empty. Meanwhile, nearer the heart of London, docking stations become full very quickly, meaning users can't park immediately. This mismatch between demand and supply has been a problem at particular docking stations for some time now. It does make you wonder why TFL haven't been able to identify a way of getting staff to replenish empty docking stations and relieve full ones quickly.

So, the scheme is rather unreliable for commuters who face tight travelling times. This has stopped the scheme growing into an effective competitor of the underground, buses or cabs.

What is really disappointing is that the scheme currently fails to reach its potential of being progressive, cutting rising transport costs for those on the lowest incomes. A recent TfL survey showed that 60% of all Boris Bike users earn over £50,000 - despite only a quarter of Londoners earning this overall.

A major reason for this is that bikers cannot pay with their oyster card. So most people are actually adding to their transport costs, not reducing them, by using the scheme. This is because many people have a daily commute from outside zone one, where Boris Bikes are not yet located. So many Londoners have to pay for the scheme on top of their typical transport costs.

Even for those living in zone one, the scheme does not really cut the high costs of travelling. With constrained supply, there is a real risk of not getting a bike. In fact, estate agents have recently revealed that house prices are growing faster in areas close to docking stations. So, especially for the poorest inside zone one, it's probably still better to get a season oyster card to avoid more expensive one-off charges for tube and bus journeys. So, again, Boris Bikes adds to, rather than substitutes, existing transport costs.

There is also a high probability of not finding a space to park at a docking station, risking a costly charge. You can see why those on more modest incomes might be put off.

Steps urgently need to be taken by Transport for London: a rapid increase in the supply of docking stations, an efficient recycling of bikes around the system, the extension of the scheme into zone 2 and, above all, the ability to pay with your oyster card.

With these measures we are likely to see an increase of people on more modest incomes using the bikes - no longer deterred from the additional costs and charges that come with Boris Bikes. London Cycle will then not just be a small novel experiment, but a true, cheaper alternative to the other big transport providers in the Big Smoke.

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