TV watchdog Ofcom has asked ITV to hand over information relating to the final of The X Factor.
The show was plunged into controversy after hundreds of viewers claimed that they could not get through to vote for Welsh runner-up Rhydian Roberts on Saturday evening.
Despite being the favourite to win he lost to Scottish singer Leon Jackson, who is now expected to land the Christmas No 1.
The regulator confirmed earlier this week that it was investigating the final of the X Factor following complaints from viewers.
The fact that Ofcom has asked ITV for the information was revealed in a letter to Culture Secretary James Purnell. It said it had also asked ITV for the full findings of its Deloitte report into problems with participation-TV on programmes such as Saturday Night Takeaway.
The broadcaster was criticised for not publishing the full report in October.
Ofcom boss Ed Richards wrote: “The Deloitte review publicly identified seven programmes or series where failures occurred (Soapstar Superstar, Ant and Dec’s Saturday Night Takeaway, Ant and Dec’s Gameshow Marathon, I’m a Celebrity…Get Me Out of Here!, X Factor, Dancing On Ice and The British Comedy Awards).
“We have therefore asked ITV for the full findings by Deloitte on each of these programmes and for all other relevant information on all of these programmes (including of course information necessary for us to be able to assess the most recent set of complaints received over the past few days).”
ITV says there were no irregularities in phone voting during The X Factor final.