By Sara Sjolin, MarketWatch

LONDON (MarketWatch) — The U.K.’s FTSE 100 index scored a 4.6% monthly advance on Friday after a volatile session where losses for Pearson PLC and Aggreko PLC kept the benchmark just below the flat line.

The FTSE 100 index /quotes/zigman/3173262/realtime UK:UKX -0.0084%  closed marginally lower at 6,809.70 and ended the week 0.4% lower.

Europe’s week ahead: ECB faces inflation test

Europe’s main central banks meet next week with the ECB under pressure to do something about the continent’s low inflation. Meanwhile, markets look forward to U.S. nonfarm payroll data and an earnings report from emerging market-focused bank Standard Chartered. Photo: Reuters

Posting the biggest loss in the index, shares of Pearson /quotes/zigman/155525/realtime UK:PSON -5.86%  slumped 5.9% after the publisher of the Financial Times said full-year operating profit declined due to weakness in its U.S. education business.

Aggreko /quotes/zigman/5750339/realtime UK:AGK -4.29%  gave up 4.3% after the temporary-power company said Chief Executive Rupert Soames will leave the firm to become CEO at Serco Group PLC /quotes/zigman/156162/realtime UK:SRP +12.10% . Shares of Serco Group rallied 12%.

Mining firms also added to the pressure, as they tracked most metals prices lower. Shares of Randgold Resources Ltd. /quotes/zigman/349729/realtime UK:RRS -2.45%  dropped 2.5%, Antofagasta PLC /quotes/zigman/139152/realtime UK:ANTO -2.28%  lost 2.3% and heavyweight Rio Tinto PLC /quotes/zigman/155899/realtime UK:RIO -0.77%   /quotes/zigman/176317/realtime AU:RIO +0.36%   /quotes/zigman/182541/delayed/quotes/nls/rio RIO -0.66% erased 0.8%.

Banks moved lower, with shares of Standard Chartered PLC /quotes/zigman/22532/realtime UK:STAN -1.21%  down 1.2% and HSBC Holdings PLC /quotes/zigman/13843/realtime UK:HSBA -0.97%   /quotes/zigman/207333/delayed/quotes/nls/hsbc HSBC -0.90%   /quotes/zigman/13834/realtime HK:5 +0.43%  1% lower.

Earlier in the day, sentiment was hurt by a negative mood in the rest of Europe after better-than-expected euro-zone inflation data eased pressure on the European Central Bank to act at its meeting next week. Economists have recently worried that the region was heading toward deflation, increasing speculation that the ECB would either cut rates or use unconventional easing measures to loosen policy at its March meeting.

However, better-than-expected U.S. datalifted European markets out of the red and helped the FTSE 100 trim losses.

Among gainers in London, shares of Old Mutual PLC /quotes/zigman/9621127/realtime UK:OML +5.85%  climbed 5.9% after the investment firm lifted its full-year dividend and said adjusted operating pretax profit rose last year on a constant-currency basis.

William Hill PLC /quotes/zigman/306491/realtime UK:WMH +6.08%  gained 6.1% after reporting an increase in full-year profit as it benefited from a strong revenue at its online business.

Mondi PLC /quotes/zigman/430079/realtime UK:MNDI +5.89%  advanced 5.9% after the paper and packaging firm reported a 22% rise in headline underlying operating profit for 2013.

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