By Tricia Wright and Sudip Kar-Gupta
LONDON (Reuters) - Britain's top equity index rose on Thursday on gains in healthcare stocks, led by AstraZeneca (L:AZN) on speculation rejected U.S. suitor Pfizer (N:PFE) might make another bid.
AstraZeneca rose 3 percent while domestic rival GlaxoSmithKline (L:GSK) advanced 1.2 percent, adding the most points to the FTSE 100 by some margin.
Beaufort Securities sales trader Basil Petrides said there was a good chance Pfizer would come back with a new bid, and that shareholders would put pressure on AstraZeneca to respond.
"AstraZeneca can invite Pfizer back for talks, and that's what is driving up the shares," he said.
AstraZeneca snubbed a Pfizer bid earlier this year.
But while British takeover rules mean deal talks could be back on the cards as early as Aug. 26, following the ending of the first of a two-stage cooling-off period, many investors and analysts see the year-end as a more likely time for any return.
Irish building supplies group CRH (L:CRH) also saw good gains, up 2 percent, with traders citing a rating upgrade to "market-perform" by Bernstein, partly on valuation grounds.
The blue-chip FTSE 100 index (FTSE) closed up 22.18 points, or 0.3 percent, at 6,777.66 points, approaching three-week highs touched earlier this week.
The market was little changed after July data showing British retail sales grew at a weaker pace than expected and public finances posted a small deficit.
Major mining stocks underperformed, with the FTSE 350 Mining Index (FTNMX1770) slipping 0.6 percent after a disappointing manufacturing survey from China, the world's biggest metals consumer.
Growth in China's vast factory sector slowed to a three-month low in August as output and new orders moderated, the survey showed, reviving concerns about the economy.
(Editing by Alison Williams)