Blue chip stocks were lifted in afternoon trading as investors were reassured by solid jobs data.
The FTSE 100 Index rose 32.3 to 6698, after a slight fall in UK unemployment to 1.63 million between May and July showing there is no current "Brexit effect" on the jobs market.
The FTSE 250 Index climbed 28.7 points to 17689.7, as the Office for National Statistics (ONS) revealed the jobless count fell by 39,000 in the period.
However, the ONS data did show that average earnings, excluding bonuses, rose by just 2.1% year-on-year, a fall of 0.2% on a month ago.
IG market analyst Joshua Mahony said: "The deterioration in average earnings and a rise in claimants were offset by a significant revision to the claimants figure for July".
Housebuilder Galliford Try was the best performer in the second tier after it posted a record annual profit up 18% to £135m ($178m, €159m) in the year to the end of June, after the group completed 11% more homes, totalling 3,078 in the period.
Shares lifted 83p to 1214p, as the firm added it is well-placed to withstand the uncertainties of the Brexit vote.
In afternoon trading the biggest risers in the FTSE 100 Index were Admiral Group (+50p to 1991p), Glencore (+4.5p to 181.6p), Shire (+100p to 4906p), Randgold Resources (+150p to 7505p) and 3i Group (+12.5p to 628.5p).
The biggest fallers in the FTSE 100 Index were EasyJet (-44p to 1090p), Taylor Wimpey (-2.7p to 150.6p), Burberry Group (-19p to 1255p), International Airlines Group (-5.6p to 414.1p) and Dixons Carphone (-4.7p to 367.8p).
In afternoon trading the biggest risers in the FTSE 250 Index were Galliford Try (+83p to 1214p), Softcat (+15.2p to 334p), Hochschild Mining (+11p to 266.6p), Genus (+77p to 1964p) and Vectura Group (+4.1p to 136.8p).
The biggest fallers in the FTSE 250 Index were Ocado Group (-21.3p to 256.7p), Debenhams (-2.2p to 58.4p), CYBG (-8.7p to 250.3p), PayPoint (-34p to 1006p) and Sports Direct (-9.4p to 304p).