Carlton Communications is to buy Welsh television broadcaster HTV from Granada Media for £181m sterling.
Under the deal, Granada Media will acquire Carlton's 20% stake in southeast England channel Meridian Broadcasting, taking its stake in Meridian to 99.92%.
Following the acquisition, Granada Media will own ITV regional licences broadcasting to around 35 million viewers, or over 60% of the British population.
Carlton and Granada together control 93.9% of ITV, while Scottish Media holds the remaining 6.1%. Granada last month took a 45% stake in TV3.