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* FTSE 100, mid caps up 0.3 pct
* Barclays drops after Q3 results, IB division weak
* Commodities stocks, staples support index
LONDON, Oct 26 (Reuters) - A rise among commodity-related stocks kept the UK's top share index afloat on Thursday, as Barclays took a tumble following its third quarter update.
The blue chip FTSE 100 was up 0.3 percent at 7,466.27 points by 0902 GMT, while mid caps also gained 0.3 percent.
Barclays was the standout faller, down 6.7 percent after missing estimates for its third quarter profit on the back of a weak trading performance at its investment banking division.
Barclays has been the worst-performing UK bank on the FTSE 100 this year, down 17.6 percent year to date.
Barclays' results contrasted with Lloyds', whose shares ended Wednesday's session with a slight gain despite an initial wobble.
"The main thing (with Barclays) is there's been a big drop in the income from the investment bank, which is more of a market-wide issue ... and probably a bit of sideways movement in the rest of the business," Laith Khalaf, senior analyst at Hargreaves Lansdown, said.
"It's a bit of a damp squib of a set of results."
Barratt Developments was also among the biggest fallers, down 3 percent after going ex-dividend, as was mid cap Galliford Try, which dropped 5.6 percent on the FTSE 250.
So far the British third-quarter results season has been marred by a number of large share price drops from firms such as GlaxoSmithKline and Whitbread, as well as profit warnings from Pendragon and Dialight earlier in the week.
"If you look at UK domestic firms, there's quite a lot of bad news that's expected because Brexit is hanging over results," Hargeaves Lansdown's Khalaf said.
Estimates from Morgan Stanley show that earnings are expected to grow by more than 20 percent in the United Kingdom in 2017, against 12.6 percent growth for MSCI Europe.
A high proportion of Britain's earnings growth is driven by the heavyweight energy sector, however, and is also helped by a weaker pound.
British earnings growth is expected to weaken in 2018 and 2019, according to Morgan Stanley estimates.
More broadly on the day, a rise in big consumer goods stocks such as British American Tobacco and Unilever added the most points to the index, while gains for miners Rio Tinto, Anglo American and BHP Billiton also supported.
(Reporting by Kit Rees)