The FTSE 100 Index closed 10.6 points lower at 5248.5, as falls among retail stocks offset some strong gains.
BT soared 23p stronger at 279p, its highest close since the start of April, as the City lapped up an upbeat set of results.
Other stocks pushing ahead included 3i, which soared 6% up 40p at 762p, on news it was selling budget airline Go to easyJet. EasyJet also rose 50p to 510p - an 11% leap.
Retailers were some of the session's heaviest fallers. Next lost 51½p at £10.50 to become the day's biggest loser after disappointing the City with 15-week sales figures.
Kingfisher was also down, losing 8p at 375p after a group of shareholders at French DIY firm Castorama last night rejected its £3.2 billion offer for a 45% stake.
GUS lost 19p at 647½p, off 3%. The retailer is planning to float its Burberry prestige brand but news last night that Punch Taverns has pulled the plug on its London debut weakened sentiment in the new issues market.
Among smaller stocks, N Brown slipped 4½p at 244p. It posted full-year figures in line with expectations today, but some analysts had been hoping for more than a 6% rise in sales in the 10 weeks since the year end.
But Selfridges gained 3½p at 335p after showing sales at its flagship Oxford Street shop were improving.
Back in the FTSE 100, property group British Land was a large riser after CSFB upgraded its rating on the UK real estate sector. It gained 28½p at 628½p.