Channel 5 owner Richard Desmond is considering putting the broadcaster on the market for more than 700m pounds, reports have claimed. Desmond, whose company Northern & Shell bought the channel for £103.5m in 2010, successfully returned the business to profit during the three-and-a-half years it has been under his ownership. A Northern & Shell spokesman said: "As a media group with a broad portfolio of assets, we are often the subject of speculation, but it remains our policy not to comment on these matters."Barclays has reportedly been retained as an adviser to any sale. However, early last spring Desmond was rumoured to be taking "soundings" from broadcast rivals, including ITV, about potential interest in buying Channel 5.Northern & Shell may seek more than £700m for the channel, or 10 times anticipated pre-tax profit for 2013, according to estimates by the Financial Times, much higher than analyst calculations of £500m-plus from Espirito Santo last year.Northern & Shell is also the owner of the Express and Star newspapers and OK! Magazine. NR