Takeover talk buoyed the London market on Thursday as rumours did the rounds about a possible bid for Morrisons (LON:MRW).
The supermarket's shares rose 7.7p, or 4.7%, to 170.8p on reports that South African billionaire Christo Wiese may be looking to add to his UK acquisitions of retailer New Look and gym group Virgin Active.
Wiese, who has an estimated £4.2bn fortune, is said to be eyeing UK supermarkets despite turmoil in the sector as they combat competition from discounters.
The news boosted other supermarkets, with Tesco (LON:TSCO) gaining 2.9p to 187.75p and Sainsbury (LON:SBRY) advancing 5.6p to 242.7p.
The FTSE 100 Index was on course for its biggest one-day gain in a week, rising 82.48 points to 616, as a bank holiday in economically turbulent China lifted pressure on stocks.
The European Central Bank (ECB) left interest rates unchanged on Thursday at record lows.
Attention was set to turn to ECB president Mario Draghi's press conference, where traders are likely to seek hints about potential further quantitative easing.
DailyFX currency strategist Ilya Spivak said: "With the Greece fiasco now on the backburner, traders will focus on the possibility that policymakers are mulling an expansion of stimulus efforts."
Reduced market tension over Greece also helped to lift Eurozone services activity in August back to the four-year high in June after a dip in July.
But the UK's service sector purchasing managers index fell to 55.6 last month from 57.4 previously, although any figure above 50 still denotes growth. Survey author Markit said it was the weakest rate of expansion in more than two years.
Markit economist Chris Williamson said: "As such, the UK economy looks set to grow by 0.5% in the third quarter, down from 0.7% in the three months to June, with the ongoing upturn almost entirely dependent on the service sector."
The FTSE 100 Index leapt 105.15 points to 6188 in early trading, helped not least by the fact that Chinese markets were closed for a bank holiday and World War II parade.
The Dow Jones, which closed nearly 300 points higher on Wednesday night, was set to open 73 points higher.
In corporate news, bus and train operator Go-Ahead (LON:GOG) backtracked 176p to 2360p after it warned of a year-long delay in hitting bus profit targets.
Barclays (LON:BARC) gained 3p to 256.8p as the banking group agreed to sell its retail banking, wealth and investment management businesses and part of its corporate banking business in Portugal to Bankinter.
But EasyJet (LON:EZJ) ascended 83p to 1755p after the budget carrier increased its profit forecast following a record August.
There was also good profit news from Jet2 airline operator Dart Group (LON:DTG) and recruitment firm Empresaria (LON:EMR).
Empresaria, whose shares rose 9p to 81p, said it expected to beat market estimates this year after a strong first half.
Dart's stock lifted 58.25p to 500p as it said strong summer trading would result in annual results being materially above market expectations.
Elsewhere, antibiotics group Motif Bio (LON:MTFB) was 4.5p healthier at 65.25p as US regulators granted fast-track designation for iclaprim intravenous (IV) to treat skin infections and bacterial pneumonia.
Metal miner Amur Minerals (LON:AMC) hardened 0.75p to 17.5p as it said a deposit at its Kun-Manie nickel-copper project in Russia was bigger than expected.