Under-fire FCC chairman Tom Wheeler has sought to shore up his turbulent position by saying his organisation will begin to call out service providers whose broadband speeds fail to live up to their promises.

Written warnings will be sent to companies who cannot deliver advertised download speeds or promised levels of performance, with continued under-performers named and shamed in public.

The news comes as the FCC looks to respond to the 2014 Measuring Broadband America report, which found that although most DSL and cable providers are able to provide promised speeds on the whole, several major companies are still falling behind.

The month-long survey found that the US’s largest two providers, Verizon and AT&T, both fell well short of their targets, delivering only 80% and 79% of their advertised speeds during peak hours respectively.

According to recent figures from Strategy Analytics, Verizon has 122m subscribers across the US at the end of Q1 2014, with AT&T recording 116m customers, meaning a significant number of people are not seeing the performance they signed up for.

"While it’s encouraging to see that in the past these reports have encouraged providers to improve their services, I’m concerned that some providers are failing to deliver consistent speeds to consumers that are commensurate to their advertised speeds," Wheeler said.

"As a result, I’ve directed FCC staff to write to the underperforming companies to ask why this happened and what they will do to solve this."

In comparison, leading cable carriers Comcast and Time Warner both delivered better than their advertised speeds during peak hours, recording 113% and 101% rates respectively.

Wheeler has come under attack in recent weeks following the FCC’s stance on net neutrality, with many media commentators criticising the body’s U-turn on allowing allow telecoms companies to financially discriminate between traffic, which they fear will lead to ‘two-tier’ internet access speeds.