Blue chip shares lifted in afternoon trading with traders cheered by positive factory output data and ignoring closer polls ahead of next week's general election.
The FTSE 100 Index was up 27.7 points to 7547.6, as manufacturing production slipped back from a three-year high in April, but still showed robust growth in May buoyed by a weak pound and rising export orders. The FTSE 250 lifted 36.1 points to 20008.3.
Production fell to 56.7 in May from 57.3 the month before, according to the closely-watched Markit/CIPS UK Manufacturing Purchasing Managers' Index (PMI). The mark was just above economists' expectations.
The reading is below April's 2013-high, but still pleasantly surprised economists. The pace of jobs growth was the fastest since 2014, said Markit.
A number of differing election polls were also released with forecasts for the morning after the election, which ranged from a hung parliament to a large majority for Prime Minister Theresa May, ahead of Brexit talks with Brussels.
IG market analyst Joshua Mahony said: "The FTSE is punching higher, with traders largely disregarding the chances of a win for Labour leader Jeremy Corbyn and impact it would have upon Brexit negotiations."
He added: "The weak pound remains a significant boost for UK products, which in turn has helped the manufacturing industry to post the second highest PMI reading in almost three years."
The biggest afternoon risers in the FTSE 100 Index were Paddy Power Betfair (+330p to 8400p), 3i Group (+34.5p to 929.5p), Convatec Group (+9.1p to 329.1p), Micro Focus International (+64p to 2458p) and British Land Company (+12.5p to 646.5p).
The biggest afternoon fallers in the FTSE 100 Index were Taylor Wimpey (-10.8p to 192.3p), Mediclinic International (-28p to 780.5p), National Grid (-35p to1054.5p), Marks & Spencer (-9.1p to373.4p) and EasyJet (-25p to1389p).
The biggest afternoon risers in the FTSE 250 Index were Inmarsat (+48.5p to 848.5p), Auto Trader (+18.4p to434.5p), Sophos Group (+17p to469.4p), Caledonia Investments (+97p to2978p) and Restaurant Group (+12p to376.1p).
The biggest afternoon fallers in the FTSE 250 Index were FirstGroup (-8.8p to141p), Nostrum Oil & Gas (-28p to503.5p), Aldermore Group (-12.7p to231p), Clarkson (-96p to2584p) and Daejan Holdings (-235p to6550p).