** Weir on the verge of a surprise deletion fromthe FTSE 100 if the co underperforms Informa byanother 80 bps by the close on Tuesday
** Current market cap of £3,621 bln 0.8 pct higher thanInforma (£3,595), the stock in 111th place and thereforeeligible for promotion if it passes Weir
** Bulge-bracket trader says if Weir is deleted selling frompassive flows would equal c.2.1 mln shares, though second tradersays stock could be defended by active holders to avoid fall
** Stock brought into contention after weak FY results onFeb. 25 saw shares fall 11 pct
** Other likely moves: Tullow replaced by Hikma in FTSE 100; Afren, Oxford Instruments and Game Digital replaced in FTSE 250 by AA and Virgin Money and Tullow
(RM: alasdair.pal.thomsonreuters.com@reuters.net)