A whistleblower contacted Ofcom to claim that the cable and satellite channel, licensed to broadcast in the UK and Ireland since 1993, was guilty of "unfair conduct" in its competitions dating back to the 1990s.
The unnamed complainant alleged that between 1997 and 2008, and occasionally after 2008, the Travel channel had selected winners for its premium rate phone-in competitions, rather than picking them at random.
It was claimed that Travel Channel International (TCI), operator of the channel, did this because it wanted to promote the channel to cable and satellite TV platform holders.
The complainant said that by ensuring winners lived in areas relevant to individual TV operators, the Travel Channel could show its value to local audiences, a point particularly key during times when it was in negotiations over new carriage deals.
This meant that anyone who entered the competitions but did not live in TCI's favoured areas had "no chance" of winning. The whistleblower also claimed that TCI totally dismissed any entrants via its website or postal address.
The complainant supplied Ofcom with an example of a viewer competition in 2002 which offered a four-night city and resort break in Nemacolin Resort and Spa in the US as the prize.
It was alleged that TCI had searched the list of entrants via premium rate service (PRS) telephone calls for a winner who lived in a cable area covered by a TV platform holder with which TCI was negotiating a new carriage contract.
After being contacted by Ofcom, TCI expressed its "surprise" at the claims because it believed that no PRS entry routes had been used in Travel Channel competitions since 2003.
However, Ofcom pointed out that one of the emails made available to the regulator following a search of TCI's records referred to "phone entrants".
After searching its records again, the Travel Channel admitted that on three separate occasions between May 2004 and July 2007 there was evidence of "improper winner selection".
The channel said that winners were picked by a member of staff pointing "at random" at a row on a spreadsheet of details of entrants with correct answers.
It said that "…the process of choosing a winner from among the pool of correct answers was influenced by the wish of the Travel Channel affiliate department to have a higher representation of winners from countries outside the UK".
TCI added: "We can only reiterate that these very regrettable episodes, in which strictly random procedures were not adhered to, pre-dated [the later procedures], which since August 2007 we are confident have accorded all entrants an automatic equal chance of winning…"
But Ofcom criticised the Travel Channel for allowing competitions to become "imbalanced" and favour "some entrants over others".
The regulator said that evidence of "widespread abuses" in the area of PRS came to light some years ago, leading to a massive £5.7m fine levied on ITV in 2008, and have "caused considerable damage to the reputation of the industry and undermined trust that has taken some time to be re-established".
Even though the complainant's allegations about TCI picking winners to help its carriage negotiations could not be substantiated, Ofcom said that the three confirmed cases represented a "severe compliance failure" from TCI.
However, the regulator ruled out imposing a sanction on TCI over the breaches, partially because of the length of time and patchy records presented by TCI meant that it was unable to conduct a full and fair investigation.
In addition, on the basis of the evidence put forward by TCI, Ofcom took into account that the broadcaster had not made major revenue from the use of PRS in the three admitted breaches, and the entrants had not been caused undue "financial harm".
"More generally, we noted that the Licensee had apparently not sought to use PRS in competitions, other than in two isolated cases, for a number of years," said Ofcom.
"Ofcom also noted the licensee's regret and that it had taken steps to remind staff of their responsibilities under the code and the licence."
Despite ruling out a fine at this stage, Ofcom warned the Travel Channel that it will face a "significant sanction" if further instances of compliance failure around PRS viewer competitions are reported in the future.
In a statement to Ofcom, TCI said: "The number of disadvantaged people was relatively small because Travel Channel's UK viewing share is less than one tenth of 1%... but this is not to seek to condone or minimise what happened."