BBC news programme Newsnight has called into question the validity of a controversial report claiming that extremist texts encouraging hatred of gays, Christians and Jews are available at Britain’s mosques.

Researchers for the centre-Right think tank Policy Exchange claimed to have found such publications in a quarter of the 100 mosques and Islamic institutions they visited, including London Central Mosque in Regent’s Park, which is funded by Saudi Arabia.

Many of the publications allegedly called on British Muslims to segregate themselves from non-Muslims and contained repeated calls for gays to executed and for women to be subjugated.

However, an investigation shown on Newsnight earlier this week found serious inconsistencies in some of the receipts for the purchases of the texts which form part of Policy Exchange’s report.

Several of the receipts had been printed on laser-jet printers, as opposed to being commercially produced, which would be normal practice.

Those receipts carried the wrong address for the mosque they purported to come from, and expert testimony said two receipts from mosques forty miles apart were written by the same person.

The report was the most comprehensive academic survey of its kind ever produced in the UK and was based on a year-long investigation by several teams of specialist researchers.

Policy Exchange said it found the literature was accessible both openly and “under the counter.”

They collected 80 books and pamphlets over the course of the year.

In a statement on their website Policy Exchange said they stood by their report “100%” and explained how the BBC programme came to be in a position to examine the receipts.

“During the course of a year-long investigation, our researchers were able to obtain extremist material, some of it anti-Semitic, misogynistic, separatist and homophobic, from a quarter of the representative sample of mosques and places of Islamic instruction.

“Three-quarters of the nearly 100 institutions were conversely found to be nothing other than perfectly reputable centres of Muslim worship and learning.

“In mid-October, Policy Exchange and Newsnight negotiated an exclusive deal on the release of the report, prior to its being made available to other media organisations.

“At all times, Policy Exchange acted in good faith, even volunteering to Newsnight receipts obtained in the course of the investigation to corroborate the fact that the various extremist books were indeed procured from the particular institutions identified in the report.

“The receipts are not, however, mentioned in the report and the report’s findings do not rely upon their existence. The report relies instead on the testimony of our Muslim research team.”

Policy Exchange’s research director Dean Godson accused Newsnight of making a disastrous editorial judgement by deciding not to broadcast the findings of the report in October and focusing on the receipts.

The programme’s editor Peter Barron responded on his BBC blog yesterday.

“I spoke to Policy Exchange to try to clear up these discrepancies but in the end I decided not to run the report,” he wrote.

“This is not because I “bottled” it as Mr Godson suggests, but because I did not have the necessary level of confidence in the evidence presented.

“In the days that followed we focused further on the five receipts about which we had concerns and eventually asked a forensic scientist to analyse them. This is what we found.

1. In all five cases the mosques involved said the receipts did not belong to them.

2. The expert analysis showed that all five had been printed on an inkjet printer – suggesting they were created on a PC.

3. The analysis found “strong evidence” that two of the receipts were written by the same person.

4. The analysis found that one of the receipts had been written out while resting on another receipt said to be from a mosque 40 miles away.

“Mr Godson says he stands by his report 100%. I also stand by our report 100%. I don’t think we can both be right.”