BT has unveiled a £6 billion programme to upgrade its network in a move to extend ultrafast broadband to at least 10 million homes and businesses and lay fibre optic lines to around two million premises across the UK.

The telecoms giant, which has 950,000 customers and 7,000 staff in Scotland, also pledged to improve its customer service under the major investment plans as it sought to appease regulator Ofcom, which has threatened to force a split of its Openreach fixed-line network arm.

BT announced the investment as it reported a 15 per rise in pre-tax profits to £3.03bn for the year to the end of March 2016 on revenues up 6 per cent to £18.9bn.

"The UK is a digital leader today and it is vital that it remains one in the future," said BT group chief executive Gavin Patterson. "Networks require money and a lot of it. Virgin and BT have both pledged to invest and we will now see if others follow our lead. Infrastructure competition is good for the UK and so is the current Openreach model whereby others can piggyback on our investment should they want to”

Ofcom recently stopped short of ordering a split of Openreach, but told BT it must cut prices charged for high-speed lines, install more business lines and improve business services.

Part of the three-year initiative will see BT focus on replacing its ageing copper wire that most homes rely on for internet access, with aims to roll out fibre optic cabling to two million homes and businesses – mainly in new housing developments, high streets and business parks.

A spokesman for BT Scotland said it was too early to say exactly where the money would be spent.

The company is already investing £126m in two government-backed Digital Scotland partnerships – one in the Highlands and Islands led by Highlands and Islands Enterprise and the other in the rest of Scotland led by the Scottish Government. This has so far delivered high-speed broadband to more than 580,000 homes and businesses. BT said another 1.4 million Scottish homes and businesses would have access to high-speed fibre broadband as part of its ongoing commercial investment programme.