The FTSE 100 Index leapt 1.6% today as an upbeat mood and strong start on Wall Street lent strength to the market.
London's blue chips staged a striking turnaround during the session after downbeat manufacturing and home sales figures hit the US stocks before the weekend.
But a reversal in sentiment saw the Footsie rise determinedly in late trading to end up 83.5 points at 5165.7.
In the US, investors took cheer from more takeover news from Xerox and the Dow Jones Industrial Average added 1.4% in early trade.
Nicola Poskitt, market analyst at City Index, said: "The European and US markets have turned around today, despite a poor start this morning. There is little in the way of economic data out until tomorrow therefore the move today in the indices could to be a correction to the sell off at the end of last week."
In London heating and plumbing supplies firm Wolseley led the pack, despite posting annual losses of £766m (€830.8m).
Shares jumped more than 11% or 146p to 1455p after its profits figure, excluding write-downs and restructuring costs, came in higher than expected and the company reduced its debt mountain to below £1bn (€1.08bn).
Also moving up the leaders' board was drugs firm AstraZeneca, which gained 77p to 2828.5p after a legal boost in a patent fight against generic competition to its Seroquel treatment for bipolar disorder.
Rival GlaxoSmithKline was 24p better at 1251.5p after announcing plans to launch its Lucozade energy drink across China.
Some banks were also rising as the G20 pledged reform on the sector, while Chancellor Alistair Darling told Labour's annual conference in Brighton that there can be "no return to business as usual" after the recession, with legislation planned to end automatic bonuses and curb the reckless pursuit of short-term profits.
HSBC added 19.1p to 723.3p, while Barclays rose 8p to 365p.
But part-nationalised banks Lloyds Banking Group and Royal Bank of Scotland did not benefit amid further speculation about the outcome of a state aid ruling from Neelie Kroes, Europe's competition chief.
It is thought that Lloyds could lose a sixth of its market share in Britain, while RBS will be told to make cuts on a similar scale, the FT said.
Lloyds was up 0.3p to 103.75p, while RBS was one of only a handful of fallers, down 0.4p to 51.6p.
Home Retail Group posted the biggest fall of the session after Credit Suisse downgraded the stock and said growth will depend on internet-only products that require greater marketing, making Argos's pricing more susceptible to competition. Shares fell 3% or 9.1p to 276.9p.
The announcement that the British government is to extend the car scrappage scheme to cover an extra 100,000 cars and vans had a muted reaction from the sector.
Inchcape gained some ground in the second tier, adding 0.95p to 28.17p, but fellow dealership Lookers was on the back foot - losing 3p to 57p.
The biggest Footsie risers were Wolseley up 146p to 1455p, Legal & General up 3.95p at 79p, Segro up 15.4p at 376.4p and 3i Group up 11.7p to 291.6p.
The biggest Footsie fallers were Home Retail Group down 9.1p at 276.9p, Tullow Oil down 18p at 1157p, BT Group off 1.35p at 130.85p and Royal Bank of Scotland down 0.4p to 51.6p.