It turns out that turnstiles might not be the best place to test NFC after all. Gigaom reports that Transport for London won't be introducing NFC-enabled mobile payments for the London Underground anytime soon.

The problem? Too slow.

"Unfortunately ... we found that the technology was not fast enough to complete the transaction in under 500 milliseconds, which we would require," said Transport for London customer experience director Shashi Verma in the story.

Transport for London announced last year that it would roll out mobile NFC payments in 2012. The TFL plan was based on assurances from NFC proponents that mobile phones would meet the authority's speed criteria. That didn't happen.

Verma said the Underground isn't nixing EMV, just NFC. And the nixing may not be forever.

"We are keen to see any progress the industry can make in this area," Verma told Gigaom.

Currently, London commuters can use Oyster cards on the metro transit system. The RFID chip-enabled cards work in 300 to 350 milliseconds.

For more stories like this, visit the NFC/Contactless research center.