The rip-off dealers put ticket prices up by 600 per cent

Thousands of people buying tickets for everything from Wimbledon to the Glastonbury Festival are at risk of being ripped off by sales agents, according to the Office of Fair Trading (OFT).

The watchdog, which launched an inquiry into ticket agencies last year, has this week warned consumers that prices vary considerably between agencies.

The OFT said it had also found tickets being sold at mark-ups as high as 600 per cent by secondary ticket agents, which do not work on behalf of event promoters, and on auction sites such as eBay. Even direct ticket agencies can add 30 per cent to the cost of a ticket through administration and postage charges.

Consumer group Which? said mark-ups in the primary market tended to be at least 8 per cent of the ticket price, while administration fees were charged for every individual ticket being bought - rather than just on each order. So is it still possible to buy tickets for concerts, plays and other events at their face value - or has the price on the front of the ticket become meaningless?

The only way to ensure you pay just the cover price is to physically get yourself to the box office - and even then, it's possible there will be an additional charge. You're also best to be armed with cash, as using a credit or debit card is likely to incur a fee. However, many venues no longer have manned box offices, leaving prospective customers no option but to buy their tickets through one of the many agents.

But if you do buy your ticket through an agent, you don't have to be ripped off. There's an enormous difference in the amount agencies charge - even the primary ones - so a few phone calls can get you a better deal.

Ticketmaster, See Tickets and Keith Prowse are three of the biggest primary agencies in the UK - and all charge booking fees of upwards of £4 for every ticket they sell, and postage of almost £5 for each order. But booking fees vary at each agency for each event - so if you're ordering a few tickets, you could end up saving yourself £10 or £20 just by shopping around.

If you're looking on the web, stick with well-known companies. Avoid secondary agents - they buy up tickets and sell them on, typically with an enormous premium. These agents are only worth considering if you're trying to get into a sold-out event. If you're desperate to see the men's final at Wimbledon next Sunday, there are still plenty of tickets on sale, even though the championship officially sold out months ago. The Online Ticket Shop will sort you out for £1,695, while Premier Events will sell you a seat for more than £1,800.

The only way to pay the actual cover price for a Wimbledon ticket (£79 for men's final day) is to apply through the ballot at the end of the year. However, using auction sites such as eBay, it's possible to pick up tickets at much more reasonable prices than at the secondary agents.

Before you make your purchase, the OFT advises that you make sure you know exactly where your seats will be - do they have a restricted view, for example? Make sure you find out what happens if the event is cancelled, or if your tickets don't turn up. Most primary agencies will honour a refund if a concert is cancelled, but occasionally the small print will warn you that there can be no refunds.

Although booking fees may be here to stay, the OFT says it is working with the ticket agents' trade body to design a new code of practice, and is drawing up plans with the Advertising Standards Agency to make adverts for events more transparent. Under the new rules, all adverts will have to state the face value of the ticket, and make it clear that additional charges may apply.