Shire and energy firms lift FTSE but RSA tumbles as Zurich drops bid

* Blue-chip FTSE 100 index up 0.2 pct

* RSA Insurance falls 20 pct

* Shire gains after European drug approval

LONDON, Sept 21 (Reuters) - Britain's blue-chip share index edged higher on Monday, with drugmaker Shire gaining after receiving European approval for an ADHD treatment, while energy firms tracked a rally in crude oil prices.

RSA Insurance, however, plunged 20.5 percent after Zurich Insurance Group abandoned its proposed 5.6 billion pound ($8.7 billion) bid for the British insurer.

The blue-chip FTSE 100 index was up 0.2 percent at 6,113.58 points as of 0814 GMT after falling in the previous two sessions. The UK Oil and Gas index rose 0.4 percent, helped by a 1.2 percent rise in oil prices as U.S. drilling slowed and there were concerns about planned American production at low prices.

"Energy companies are getting a lift from a bounce in oil prices, but the market really needs a catalyst to come out of the recent trading range. Any improvement in China manufacturing data due later this week could help the market," IG analyst Chris Beauchamp said.

"Individual companies will continue to be guided by news flows. Shire's rally may have further legs if they get more drug approvals, while RSA may benefit from a bid from any other company. However, after Zurich ditching the deal, other prospective buyers are likely to be very cautious."

Shire rose 2.8 percent, the top gainer in the benchmark FTSE 100 index, after it received European approval for its Intuniv tablets as a non-stimulant treatment for attention deficit hyperactivity disorder, or ADHD, in children and adolescents.

"Traders obviously hope new indication for Intuniv can help replace some of the lost sales since the drug went off-patent and began suffering generic competition," Mike van Dulken, head of research at Accendo Markets, said.

"Continued progress by Shire in ADHD keeps it ahead of game to develop the next preferred treatment, to help it recapture lost market share to what is inevitable generic competition over time."

Inmarsat shares rose 1.3 percent after the company announced its aviation broadband initiatives with Deutsche Telekom and Lufthansa. (Reporting by Atul Prakash; Editing by Hugh Lawson)