The blue-chip index edged up 0.2% by 0814 GMT, holding near its strongest level since June 8, although sluggish oil stocks limited further gains.
The domestically focussed FTSE 250 jumped 1.2%.
Wall Street's main indexes rallied overnight, with the benchmark S&P 500 closing 3% higher, after Fed Chair Jerome Powell opened the door to a slowdown in the pace of monetary tightening.
Bucking the positive mood, oil stocks fell 1.5% as crude prices dipped with uncertainty lingering ahead of Sunday's OPEC+ meeting. [O/R]
Shares of education group Pearson fell 3.5% after Exane BNP Paribas downgraded the stock rating to "neutral" from "outperform".
(Reporting by Shashwat Chauhan in Bengaluru; Editing by Sherry Jacob-Phillips)