Relentless trading on the FTSE helped it to a near 9% gain on Friday and a record one-day rise.
The swift advance of banks on the FTSE this morning may represent the clearest sign yet the UK markets view yesterday's events as the beginning of the end of a financial crisis described as the worst since the Great Depression.
The Dow Jones Industrial Average has fallen by more than 2% after markets opened in the US.
The FTSE100 plunged under the 5,000 barrier for the first time since June 2005 this afternoon while the US market fell on more bad news from AIG.
The FTSE100 plummeted beneath its 52-week low this morning following further significant losses for Halifax Bank of Scotland (HBOS).
Wall Street has taken its expected punishment upon opening this morning, with the Dow Jones slumping almost 3% in under an hour of trading.
Resources have helped the FTSE surge ahead to 5416.70, having climbed 98.30 points (1.85%.)
A string of poor retail results have hindered the FTSE's progress as the index ended the day down 47.80 points (0.89%) to 5318.40.
A slow start for retailers coupled with strong losses in Asia is weighing on the FTSE100 this morning, with London's blue-chip index down 25.60 points (0.48%) to 5340.60 so far.
The FTSE has nose-dived 49.90 points (0.91%) to 5366.20 due to more negative sentiment.