ITV chief executive Charles Allen said that ITN's current contract expires in 2008 and it will not be renewed after that date. If Allen is not able to negotiate a deal for to buy ITN, ITV will likely produce its own news in-house.
ITN is 40% owned by ITV with the remaining 60% held equally by Daily Mail & General Trust, Reuters and United Business Media, each with a 20% stake.
"Either in the remaining years of the contract, I will be able to buy the other 60% and then own the company in its entirety or, at the end of the licence, we will not contract our news with ITN. We will undertake to produce our own news in-house," Allen said.
A spokesman for ITV said: "We have made no secret of our ambitions to own ITN, but that depends on timing and price."
The Observer reported on Sunday that ITV was ITN's biggest customer and that any decision by it to end the contract in 2008 would effectively sound the death knell for the 50-year-old news company.
As well as making ITV's news, ITN makes news for Channel 4 and for more than 260 commercial radio stations through Independent Radio News.
Last year, Sky beat ITN in the race for the Five news contract. ITN had provided news to the channel since it launched in 1997. The deal was worth an estimated £6m.
Allen made his comments in a new book, 'And Finally… The News from ITN', written by veteran ITN journalist Richard Lindley.
Talk of buying ITN comes as ITV is itself the subject of intense bidding speculation with private equity groups circling the broadcaster.
It has been reported that departing United Business Media chief executive Lord Clive Hollick could be involved in a bid after it was announced he was taking a managing director role at US private equity firm Kohlberg Kravis Roberts to target UK media businesses.
Working with Lord Hollick are former BBC director-general Greg Dyke and former Telegraph Group managing director Stephen Grabiner.
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