The chief executive of Christian Legal Centre has called the decision to uphold a ban on a Christian radio advert "chilling" and "bewildering".

In May 2011, Premier Christian Radio planned to run an ad asking listeners to report their experiences of marginalisation in the workplace as a result of their faith.

"We are concerned to get the most accurate data to inform the public debate. We will then use this data to help make a fairer society," it said.

However, the Radio Advertising Clearance Centre (RACC) refused to let the advert air, claiming that it had a political objective and therefore fell under the broadcasting prohibitions on political advertising.

The decision was made to uphold the ban at an appeal held earlier this week, but the accusations of Master of the Rolls, Lord Dyson, who deemed the advert contrary to broadcasting legislation, have been criticised.

Andrea Minichiello Williams, chief executive of Christian Legal Centre called the ad "innocuous", adding that it is "startling [that it] should be deemed unlawful.

"It's clearly an attempt to gain information for the laudable aim of creating a fairer society. There is no attempt in the advert to persuade anyone to adopt a particular political position," she says.

She went on to brand the court's decision "chilling" and "bewildering", noting that there seems to be discrepancies between what is and isn't allowed in advertisements.

Williams made reference to the fact that private clinics that charge for pregnancy services including abortions are now legally able to advertise on the television and radio as of early 2012.

She referred to the billboards on double-decker buses telling those who disapprove of homosexuality to "get over it", with a reminder that Christian adverts in response to those posters were not allowed. She also mentioned another campaign by a humanist group which saw the slogan "There is probably no God, now stop worrying and enjoy your life" plastered across London.

"We have seen Christian adverts being banned in other areas whilst those of other special interest groups have been allowed," Williams said.

"There now appears to be a clear asymmetry in how Christian messages are being treated by advertising standards bodies."

Chief Executive of Premier, Peter Kerridge, has stated that the ban "represents an attack on freedom of speech".