7 things you need to know about London's contactless transport

London's transport system took a giant leap into the contactless world with the introduction of a system that lets you use your NFC-enabled debit or credit cards on the Oyster readers.

TechRadar was at the launch of the new system, which is going to have its critics, but is definitely a step forward as Transport for London yet again proves that being in charge of the world's oldest underground system is no barrier to progression.

But, you are likely to have some questions about the new system, so let us pick out some of the big issues and tell you what you need to know about contactless payment on London's network.

1. Card clash IS going to be an issue

If you've been anywhere near London's transport network in the past few months you'll have sampled the posters, announcements and promotional muggers (puggers?) telling us not to let your debit or credit card get near an Oyster reader unless you want to be charged on it.

For those of us who keep our Oysters in our wallets and have yearly or monthly passes the message is fairly stark. You are going to have to separate your cards.

Of course card clash should NOT be our problem. But we don't get a say in it.

2. If you are an occasional London traveller or a weekly pass user then this is a very good thing for you

Somewhat neatly, you'll be charged a normal fare through contactless, but if you make multiple journeys using your card you'll be capped at a day rate and then a weekly rate rather than paying for every journey.

And because it's your normal bank card there's no queuing at machines to get a paper ticket, or to top up your pre-pay on your Oyster, or even a need for an Oyster card.

3. Capping won't work for monthly or annual travellers.

Speaking to TechRadar, TfL's Shashi Verma explained that getting the system to work for weekly passes was pretty tough, but that extending that to monthly or annual passes was simply beyond current capabilities.

"The algorithm that does day and week is about most sophisticated one I've ever seen," he said. "To add monthly is a real challenge and the computation needed to do a monthly cap is a real challenge.

4. Some people are already offering up novel card-clash beating systems

EE have had something of a hit with a partnership with MasterCard on a CashonTap system and the company has confirmed that the system is usable on the London network - which means you can smugly bang your new phone down on the reader and watch the bemused tourists try and fail to do the same thing. Cruel.

And for those of you who remember BarclayCard's bPay wristbands that made a bit of a stir at festivals this year, you can get yourself one of the rubber wearables that will work on Oyster card readers as well. It's a bit of a wrist, but someone's got to try it.

5. It's coming to another city near you soon

With Chicago in the US and London now contactless, we heard talk at the event that Manchester and Birmingham are definitely maybe considering similar contactless offerings.

And there's already rumours about some of the world's other great cities keeping an eye on how London manages before unleashing their own version. Watch this space.

6. Apple's big reveal has been a bit of a boon for contactless

The announcement of Apple Pay (and the iPhone 6, iPhone 6 Plus and the Apple Watch of course) could not have been better timed, although Vema was at pains to point out "we've been working on this for years!"

The Apple Pay product may be a bit limited (at least according to PayPal!) but as consumers get more au fait with paying by tap rather than with cash or chip and pin we'll start to see contactless become ubiquitous.

7. Wearables are going to be kind of a big contactless deal

We've already mentioned CashonTap and bPay, but with Android watches hitting the headlines as hard as the likes of the Moto 360 have, the whole room was buzzing with talk of next gen payment.

Watches and jewelry are on the cards, allowing you pay, travel or cash in your loyalty vouchers without delving into your pockets. And it could well be that, as we said many moons ago on TechRadar, NFC is the real killer app for wearables.