As the session got under way, the top flight nudged past 4,200 as a hefty surge on Wall Street the night before fuelled trading.
But with US markets closed for Thanksgiving the FTSE came off its highs to close up 41.2 points at 4,185.4.
It has been stuck between the 4,000-4,200 trading range since the start of November, with any gains frittered away by profit taking.
But Peter Cogliatti, analyst at Williams de Broe, said the trends suggested any gains on US markets tomorrow could inspire further rises here.
Financial stocks were among the risers with Barclays up 9.25p to 464.25p, HSBC rising 14.5p to 760.5p and HBOS climbing 17p to 696.5p. Abbey National bucked the trend, however, losing 25p to 642.5p after JP Morgan reduced its 2003 forecast.
But the session’s biggest winner was engineering group Invensys after it completed its programme of non-core asset disposals.
The biggest blue-chip risers were Invensys, up 5p at 63.75p, Granada, up 6.75p at 95.75p, Royal & Sun Alliance, up 9.75p at 144.5p and Cable & Wireless, up 5.5p at 83.5p.
The heaviest fallers were Dixons, down 17.5p at 171.5p, Abbey National, off 25p at 642.5p, Brambles Industries, down 5.5p at 150p and J Sainsbury, off 9.74p at 290.25p.