BT's finance chief has come under fire for "messy communication" after a seemingly positive update obscured signs of tougher trading for its core consumer business.
The telecoms giant's shares were up as much as 8pc but swung violently at the end of the day to close down 2.5pc as analysts crunched the numbers to reveal the extent of competition in the broadband market.
BT had buoyed investors by lifting the lower end of its full-year profit predictions by £100m to between £7.3bn and £7.5bn and said profits could hit £7.9bn by 2022-23.
But the market sent shares down in the afternoon after analysts questioned finance boss Simon Lowth's decision to keep its cash flow outlook unchanged.
Concerns were stoked as analysts drilled into the figures and estimated turnover in BT's fixed line consumer business, which includes broadband and landlines, was down about 8pc as a result of intense competition, Covid disruption and regulation.
In a note to investors, HSBC analyst James Britton wrote: "We might assume that the higher EBITDA should translate to higher cash flow but the company simply wants to sit on free cash flow expectations for now."
"Overall, the messy communication has been a spoiler for what could / should have been a marker for a turn towards positive earnings momentum," he added. "As it is, I think this is a missed opportunity, and investors will have to be patient."
Shares in BT closed at at 99.1p - a level not seen for more than a decade - and have halved since the start of the year. BT is now worth just £9.8bn.
It came as the FTSE 100 firm suffered a pandemic-induced blow to sales and profits as its sports broadcasting arm came under pressure from disruption to live matches.
Revenues fell 8pc to £10.6bn for the six months to September as the crisis knocked sales at BT Sport following a spate of delays to top-flight football and rugby.
BT Enterprise, the division selling telecoms services to businesses, also contributed to the drop amid waning demand from small firms during the crisis.
Pre-tax profits slid by a fifth to £1bn over the period.
Berenberg analyst Carl Murdock-Smith said BT's half-year pre-tax profits would have suffered a steeper fall without a rebate for rights to postponed sporting fixtures.
Chief executive Philip Jansen said BT had delivered a "strong operational performance during exceptional circumstances" with £352m of cost savings in the first half.
He has embarked on a radical overhaul that will slash 13,000 jobs over three years and cut the number of offices by 90pc.
BT also announced plans to reinstate payments to shareholders from next year at 7.7p a share after cancelling the £2.5bn dividend to help meet the £12bn cost of upgrading the UK to full fibre.
Boris Johnson has an ambition of carpeting the nation in gigabit speed broadband by 2025, but BT has warned that target will be missed by eight years without £9bn in cuts to tax and red tape.
Openreach - BT's broadband infrastructure arm - hit "record levels" for upgrading old copper lines to ultra fast full-fibre broadband in the second quarter.
It has hooked up 3.5m homes and businesses this year and plans to stop selling copper services to about 1.8m customers by September 2021.
Mr Jansen said BT needed "clarity and help" to meet the aggressive industry targets set by ministers.
He said the business rates paid on installing new fibre lines was "counterproductive" and the government's plans to invest £5bn into bringing broadband to the countryside still needed to "get going".
The update came as revenues at mobile operator O2 fell by 9.5pc to £1.4bn during the third quarter following pressures from the pandemic and cuts to roaming charges.
The drop came despite the telecoms firm hitting a record 35.4m customers.