Britain's top share index has fallen to extend a four-day losing run after posting its worst first week of the year since 2000, hit by late falls in Shire and energy firms.
British-listed pharmaceutical firm Shire had a $US32 billion ($A45.95 billion) bid accepted for Baxalta International Inc, catapulting it to a leading position in treating rare diseases.
After rallying on the news, the stock turned lower to trade down 8.2 per cent.
While traders said the deal made strategic sense, there was some wariness over the price offered.
Analysts at UBS also said that synergies from were below media reports, although they came in at the top of UBS' own estimates and the analysts said that the new company would be cheaply valued, maintaining a "buy" on Shire.
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The blue-chip FTSE 100 index on Monday was down by 40.61 points at the close, or 0.7 per cent, at 5,871.83 points, ending in negative territory for a fourth straight session.
Last week's 5.3 per cent fall, the FTSE's biggest weekly drop since August, followed China's move to weaken the yuan, which rattled global markets.
China guided the yuan higher for a second straight session on Monday, calming investor concerns about how far Beijing wanted to see the currency depreciate.
However, with more weak data out of China over the weekend, copper sank to its lowest levels since 2009, and miners failed to hang on to early gains.
The FTSE 350 Mining sector touched its lowest level since 2004.
In late trade, oil companies also fell, trimming 8.5 points off the FTSE 100 after US crude hit its lowest level since December 2003.
Sports Direct fell seven per cent, after suffering broker downgrades following a profit warning last week.
The sports retailer has fallen 30 per cent in the six trading days so far in 2016.
"While the latest update only related to weakness over the past month we see a lack of earnings momentum in the short to medium term," analysts at Liberum said in a note, downgrading the stock to "hold" from "buy".
Defence and aerospace company BAE Systems rose 1.4 per cent after investment bank JP Morgan upgraded its rating on the stock to "overweight" from "neutral".
JP Morgan added that it expected 2016 to be a "very good year" for European defence stocks as geopolitical tensions escalated.
