* RBS chairman Hampton takes reins at GSK on May 7
* Move follows appointment of Davies to lead RBS
* GSK facing tough times; CEO's 2014 bonus cut by 51 pct (Adds detail on CEO's reduced bonus, paragraph 5)
By Ben Hirschler
LONDON, Feb 26 (Reuters) - GlaxoSmithKline said onThursday that its chairman-designate Philip Hampton would takecharge of Britain's biggest drugmaker from May 7, an earliertransition than initially anticipated.
Hampton, who chairs Royal Bank of Scotland, wasnamed as the pharmaceutical company's next chairman lastSeptember, but GSK said at the time he might not take up theposition until Sept. 1, 2015, if he could not be released fromother commitments.
In the event, Hampton is now able to take over with effectfrom the drugmaker's next annual meeting, following theappointment of Howard Davies as his successor at RBS.
Hampton is taking over at a testing time. GSK was hit lastyear by a record fine of nearly $500 million in China forbribing doctors and has disappointed investors with weak salesof its core respiratory drugs.
The poor performance was reflected in a big cut in the bonuspaid to Chief Executive Andrew Witty, according to the company'sannual report released on Thursday. Witty was awarded a bonus of917,000 pounds ($1.4 million) for 2014, a reduction of 51percent compared to 2013.
GSK is hoping that a $20 billion-plus asset swap withNovartis, which is due to close next week, will helprevive its fortunes, although the deal promises a long-term pathto more sustainable growth rather than any short-term fix.
Hampton will replace Chris Gent, who has chaired GSK since2005, having previously led mobile phone company Vodafone during a period of rapid growth.
Some analysts believe Hampton could usher in a period ofsignificant change at GSK. Witty has already suggested that thecompany could consider spinning off some component units.
Hampton has been chairman of RBS since 2009, when he wasparachuted in to help rescue the bank following its 45 billion-pound bailout during the financial crisis.
He has led RBS through a turbulent period during which itshed assets worth 1 trillion pounds to rid itself of toxicloans.
Hampton joined GSK's board on Jan. 1 and will become deputychairman of the group on April 1.($1 = 0.6486 pounds) (Editing by Greg Mahlich/Ruth Pitchford)