Investors showed their relief as multinational gas utility company National Grid (NG) avoided being broken up on conflict of interest grounds by regulator Ofgem.
The good news sent the stock 1.4% higher to 947.4p and provided a welcome boost to the blue chip index, which was not swayed by a mass of retail trading updates.
The pound continued its rally against the dollar to $1.23, which negatively affected the FTSE 100's many overseas earners.
West Texas Intermediate and Brent crude oil rose over 1.2% to $53 and $56 per barrel, respectively.
Gold gained 0.7% to $1,204 per ounce and copper climbed 1.8% to $5,842 per tonne.
On Wall Street, the S&P 500 and Dow Jones slumped 0.7% on opening as President-elect Donald Trump failed to clarify how he will boost economic growth.
Hong Kong's index the Hang Seng was 0.8% lower and Chinese index SSE Composite fell by 0.5%.
Marks & Spencer (MKS), which was behind the 'Mrs Claus' Christmas campaign, beat forecasts for Christmas trading as it reported its first quarterly rise in underlying clothing and homeware sales in nearly two years.
Online fashion retailer ASOS (ASC) planned to accelerate its infrastructure investment on expectations that its sales will rise by nearly 30% this year following fantastic festive trading.
Department store chain Debenhams (DEB) enjoyed a 5% rise in like-for-like sales in the seven-week Christmas period. Investors were encouraged by plans to sell more beauty and gift products rather than clothing, as this is one of the most competitive divisions in retail.
Superdry brand owner SuperGroup (SGP) posted a more than a 30% rise in revenue from £254.7m to £334m.
Pram pusher Mothercare (MTC) returned to sales growth in its third-quarter in the UK, which was supported by a rise in online orders.
Britain's biggest retailer Tesco (TSCO) capped a year of recovery on 0.7% rise in underlying Christmas sales in its home market. It was a solid performance over the key festive period, but did not quite match the updates from Sainsburys (SBRY) and Morrisons (MRW) earlier this week.
Primark owner Associated British Foods (ABF) said total sales at the discount fashion store climbed 11% in the 16-week Christmas period as it stuck to its forecast to make progress in group annual operating profit. The market honed in on flat like-for-like sales due to slower growth in Germany and the Netherlands, marking the stock lower.
Furniture retailer Dunelm (DNLM) reported like-for-like sales for the second quarter improved 0.2% on higher seasonal and online sales. The stock retreated 6.9% to 742p.
Online electrical retailer AO World's (AO) UK business experienced slower growth with ao.com revenue up 10.3% year-on-year and overall UK revenue up 8.9%. Investors were unforgiving, marking the stock 11.9% lower.
FTSE 100 RISERS AND FALLERS
Housebuilder Barratt Developments (BDEV) suffered a year-on-year drop in the number of homes built in the second half of 2016 as it completed fewer properties in London.
FTSE 250 RISERS AND FALLERS
Recruiter Hays (HAS) reported higher quarterly net fees on Thursday helped by growth in continental Europe and Asia Pacific. Investors marked the stock down on tough conditions in Britain.
Media reports that Bovis (BVS) allegedly paid incentives to persuade buyers to move into unfinished homes hit the stock by 2.4%.
SMALL CAP RISERS AND FALLERS
Edenville Energy (EDL) started trial mining at its Rukwa coal project in Tanzania and will focus on run-of-mine coal stockpile. The market surged to invest as the stock soared by 75%.
Insurance manager STM's (STM) pricing strategy paid off as it expects an increased level of recurring revenue over the next few years. The news triggered a share price rally of 24.6% to 47.3p.
North Sea-focused oil producer Premier Oil (PMO) said full-year revenue slipped 10% year-on-year in preliminary results, despite production levels hitting an upgraded target.
Oil and gas company Mayan Energy (MYN) plummeted 31% as its Shoats Creek well struggled due to a blockage, which stunted gas production.
Delays at a key project operated by Tertiary Minerals (TYM) and the need for project acquisitions dragged its share price 20% lower.