An advert that displayed a pool of blood next to a Bible attracted the biggest number of complaints to the Advertising Standards Authority last year.

553 complaints from Christian groups such as the Evangelical Alliance and Christian Voice claimed that the Gay Police Association advert promoted religious hatred.

The GPA advert said: “In the last 12 months, the GPA has recorded a 74% increase in homophobic incidents, where the sole or primary motivating factor was the religious belief of the perpetrator.”

The Advertising Standards Authority ruled in October that the advert, which appeared in the diversity supplement of The Independent to coincide with EuroPride last July, may have caused offence to Christians and the statistics in the advert had not yet been verified.

The ASA upheld claims that the imagery and text may cause offence to Christian readers and criticised using images of blood as not all the offences mentioned may have involved violence.

The Gay Police Association (GPA) expressed outrage at the ASA decision that it had insufficient evidence to back up a controversial advert linking religious beliefs to homophobic attacks.

The Crown Prosecution Service decided that it would not be pursuing a prosecution against the GPA, but an internal investigation was carried out.

The ASA did not uphold 127 complaints about same sex kisses in adverts by French Connection and 89 about a short gay kiss in a Dolce Gabbana ad.

12,800 adverts drew complaints last year, a record high. The ASA has seen a rise in concerns about online advertising.