A scheme to ensure rural Britons can get a decent broadband service is under threat after TalkTalk branded it "legally questionable" over plans to allow BT to recover the costs through higher wholesale charges.

The comment from TalkTalk chief executive Tristia Harrison will be viewed as a threat to launch High Court action to block the scheme.

Ms Harrison spoke out after Ofcom announced that providing decent broadband to 1.4 million rural homes and businesses would add less than £2 a year to wholesale charges across the country.

BT has offered to cover the upfront costs of between £450m and £600m in exchange for price increases across the whole market. It wants to install new technology that will deliver data over long telephone lines at more than 10 megabits per second, the minimum speed required to access everyday services such as video streaming, according to Ofcom.

Ms Harrison said: "We fully back the Government’s ambition to give every home decent broadband as quickly as possible, but the current offer on the table is legally questionable, and will be more complicated and more expensive to implement than it may at first appear.

"It’s critical Government and Ofcom stand up for customers, and deliver high speed broadband for everyone, in a transparent and cost-effective way that preserves competition.