* FTSE 100 falls 1.8 pct, shrugging off UK PMI data
* Oils, banks, miners and Vodafone top-weighted losers
* Food retailers, BAE, Drax up, offering some respite
LONDON, June 3 (Reuters) - Britain's blue-chip share index shed 1.8 percent by midday on Wednesday, led by weakness in banks, commodity stocks and index heavyweight Vodafone <VOD.L>, which traded ex-dividend.
By 1034 GMT, the FTSE 100 <
> was down 80.22 points at 4,396.80, shrugging off a survey showing that UK services sector activity unexpectedly returned to growth in May.Banks took the most points off the index, with Barclays <BARC.L> down 5.2 percent, extending the previous session's 13.5 percent decline.
Abu Dhabi government-owned International Petroleum Investment Company on Tuesday sold a more than 11 percent stake in the British bank.
HSBC <HSBA.L> fell 3.5 percent as traders cited market talk of Saudi conglomerate Saad Group [
] selling down in Europe's biggest bank. Both Saad and HSBC declined to comment.Saad's stake fell just under 3 percent in December, meaning it no longer needed to disclose changes in its holdings.
Within the sector, Royal Bank of Scotland <RBS.L>, Lloyds Banking Group <LLOY.L> and Standard Chartered <STAN.L> were off 1.8 percent to 4.2 percent. On the economic front, Britain's service sector staged a surprise return to growth in May after an increase in new business and the most optimistic outlook since October 2007, the monthly services PMI survey showed. [
]But the news did not deter investors from sending the index lower.
"Return to growth ... is good but the question is how sustainable it is going to be, how rapidly the economy is going to grow from here," said Peter Dixon, UK economist at Commerzbank.
"The data today did not give us any insight how far and quickly we are going to grow. There is still a huge number of structural issues in the economy which might prevent growth from picking up."
Later in the session, U.S. ADP employment and factory orders data will be in focus.
Oil producers were other standout losers as crude prices <CLc1> ticked lower. BP <BP.L>, Royal Dutch Shell <RDSa.L>, BG Group <BG.L>, Tullow Oil <TLW.L> and Cairn Energy <CNE.L> dropped 1.7 percent to 4.1 percent.
In the mining sector, BHP Billiton <BLT.L>, Rio Tinto <RIO.L>, Xstrata <XTA.L>, Anglo American <AAL.L>, Antofagasta <ANTO.L>, Lonmin <LMI.L> and Vedanta Resources <VED.L> lost between 1.6 and 4.8 percent.
Also on the downside, Vodafone sank 4.9 percent after going ex-dividend.
Cable & Wireless <CW.L>, International Power <IPR.L>, National Grid <NG.L>, Rexam <REX.L> and WPP <WPP.L> also fell after trading ex-dividend.
FOOD RETAILERS, TOBACCO SUPPORT
Food retailers were also in demand, after Cazenove upgraded the sector to "neutral" from "underweight". Tesco <TSCO.L>, Morrison Supermarkets <MRW.L> and Sainsbury <SBRY.L> put on between 0.8 and 2.7 percent.
BAE Systems <BAES.L> took on 2.3 percent after Cazenove repeated its "outperform" rating on the defence contractor maintaining that the stock "stands out as a value play at current valuation levels."
Power station operator Drax <DRX.L> advanced 1.9 percent, boosted by an upgrade to "equal-weight" from Morgan Stanley.
Cigarette makers also traded in positive territory after Citigroup issued a bullish note on them. British American Tobacco <BATS.L> put on 0.2 percent and Imperial Tobacco <IMT.L> added 0.9 percent.
Lloyd's of London insurer Amlin <AML.L> fell 1.8 percent as it placed 23.5 million shares to help fund its purchase of Fortis Corp Insurance, a provider of corporate property and casualty insurance, from the Dutch government for 350 million euros ($497.5 million). (Editing by Rupert Winchester)