By Aby Jose Koilparambil and Yadarisa Shabong
(Reuters) -Hundreds of GSK workers have voted to stage a series of walkouts at UK manufacturing sites in May over a dispute over pay, in what could be a first at the British drugmaker, labour union Unite said on Wednesday.
Unite said its 750 members voted to go on strike, having turned down the company's "significantly below inflation rate pay offer" of a 6% increase and a one-off lump sum of 1,300 pounds ($1,615).
A GSK spokesperson said the company was "disappointed" that Unite had decided to strike "despite receiving a final offer", which it called "an overall package equivalent to a 9.7% increase".
GSK said the strikes by Unite members, who account for about 20% of its manufacturing workforce, were not expected to cause any significant supply disruption.
Elevated levels of inflation have outstripped wage growth for most British workers and labour unions representing workers across sectors - from nurses to transport staff - have been on strikes for more than six months now demanding pay increases.
Britain was the only country in western Europe with double-digit inflation of 10.1% in March after it fell less than expected, data showed on Wednesday.
The strikes will be spread throughout May with workers at all six GSK sites - Barnard Castle, Irvine, Montrose, Ware, Worthing and Ulverston - striking on different dates at different times to maximise the effectiveness of the industrial action.
In May last year, Unite called off strike action after GSK lifted pay for its workers.
($1 = 0.8051 pounds)