With investors initially switching into defensive asset classes such as gold and bonds, London's top flight spent much of the session in the red before later rallying to finish a difficult week 11.1 points higher at 6749.5.
Strong results on Wall Street, led by Google and Honeywell, were an important factor in the recovery after Thursday's downing of a passenger jet over Ukraine and Israel's launch of a ground offensive into Gaza sent markets lower.
Airline stocks had a steadier session, with British Airways owner International Airlines Group just 0.8p lower at 329.9p and easyJet 7p higher at 1348p. Thomas Cook and TUI Travel fell 2p to 122.7p and 0.2p to 372.1p respectively.
One factor continuing to weigh on the travel sector is the price of oil, but there was some respite today after initially rising to 104 US dollars a barrel on fears that new sanctions against Russia could disrupt global supplies.
The pound was slightly lower against the US dollar at just below the 1.71 barrier, while it was flat against the euro at 1.26.
Investors were also helped by a return to merger and acquisition activity after an agreed £31 billion deal to buy Hampshire-based drugs maker Shire.
AbbVie, the US company behind rheumatoid arthritis treatment Humira, met a Friday deadline to confirm an offer for Shire, having increased its offer price from the £27.2 billion seen in May.
Shire rose 190p to 4996p folowing the cash and shares deal.
ITV was also in the takeover spotlight as the acquisition of BSkyB's stake in the coAmmercial broadcaster by Virgin Media owner Liberty Global excited media investors for a second day in a row. The stock rose 4 per cent or 7.4p to 202.6p.
Royal Bank of Scotland was a major faller after the Competition and Markets Authority (CMA) announced it is considering a full-scale inquiry into the sector.
The CMA said key parts of UK banking lacked effective competition and failed to meet the needs of personal consumers or small and medium-sized enterprises.
With the watchdog refusing to rule out a break-up of the big four banks, RBS fell 2 per cent or 4.5p to 319.2p but Lloyds Banking Group weathered the storm as its shares rose 0.25p to 73.42p.
Elsewhere in the top flight, drugs firms AstraZeneca and GlaxoSmithKline benefited from the Shire deal as their shares rose by 25.5p to 4340p and 9.5p to 1559p respectively.
Other risers included utility Severn Trent, which lifted 40p to 1926p as investors switched into more defensive stocks.
The biggest FTSE 100 risers were Shire up 190p to 4996p, ITV ahead 7.4p at 202.5p, British Land up 17p at 718p and BSkyB ahead 20p at 917.5p.
The biggest fallers were GKN down 5.7p at 348.6p, Royal Bank of Scotland off 4.5p at 319.2p, Hargreaves Lansdown down 14p at 1101p and London Stock Exchange off 24p at 1926p.