Shares in ITV plunged on Wednesday after its biggest investor sold half its stake in the broadcaster amid rumours of a looming takeover offer.

Liberty Global has owned around 10 per cent of the broadcaster since 2015.

But the US media giant, led by telecoms tycoon John Malone, said last night it was selling about half of its stake, worth around £140million.

BNP Paribas and Deutsche Bank are working on the deal. Liberty had been tipped as a potential buyer of ITV given its large shareholding, or a major player in any takeover.

Shares in ITV closed flat at 74.55p last night before the Liberty announcement.

ITV shares slumped 8.8 per cent to 68p in early trading on Wednesday. They have lost 11 per cent over the last 12 months and more than two-thirds since Liberty first bought its stake.

The broadcaster has faced intense competition from US streamers such as Netflix and a downbeat advertising market.

Loss: Liberty Global, led by telecoms tycoon John Malone (pictured), said last night it was selling about half of its stake in ITV, worth around £140m