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* FTSE 100 down 0.4 pct
* Shares in oil producers, miners weigh
* Aston Martin plans IPO
By Kit Rees
LONDON, Aug 29 (Reuters) - The UK's top share index dippedon Wednesday, weighed down by commodities-related stocks asoptimism over progress in global trade relationships has largelyfizzled out.
The blue chip FTSE 100 index was down 0.4 percent at7,587.75 points terms by 0900 GMT.
The FTSE index underperformed broadly flat European equitymarkets, as sentiment turned cautious.
While investors have been optimistic over a proposed tradedeal between the United States and Mexico, questions remain overwhether Canada will also agree to the revised trade terms.
A looming deadline on U.S. tariffs with China also keptmarkets on edge.
"There is still a little optimism doing the rounds in lightof the US-Mexico trade deal, but investors haven’t been givenanother reason to buy into the market," David Madden, marketanalyst at CMC Markets UK, said.
Shares in UK-listed oil and gas firms took the most pointsoff the index, with BP and Royal Dutch Shelldown 0.6 percent and 1.2 percent respectively as the price ofoil slid.
Shares in mining companies were also on the backfoot asworries over Chinese demand and a stronger dollar hit the priceof London copper.
Glencore, Rio Tinto BHP Billitonand Anglo American all retreated between 0.5 to 1.5percent.
Big consumer stocks also added to the pressure on the index.British American Tobacco and Diageo were down0.9 percent and 0.2 percent respectively.
Among outstanding movers, shares in Bunzl rose 3.5percent and were the biggest gainers.
The business supplies distributor reported first-halfearnings in the previous session and saw its shares closeslightly lower, so Wednesday's bounce was somewhat of a recoveryas investors digested Bunzl's results.
The UK's mid cap index was also subdued, trading 0.1percent lower. Nerves over the possibility of a 'no-deal' Brexithave contributed to a lacklustre performance for UK equities,with the FTSE 250 up just 0.6 percent this year, while the FTSE100 is down 1.2 percent.
This is compared with a 0.3 percent decline for euro zonestocks.
In a sign of confidence, however, luxury carmaker AstonMartin set out plans to float on the London Stock Exchange,hoping to complete the flotation this year.
"The brand strength is unquestionable but at the end of theday some investors will only want to get involved if thebusiness can sell more units than it did in the previous yearand at a higher price, and continue this trend ad infinitum,"said Russ Mould, investment director at AJ Bell.(Reporting by Kit Rees, writing by Andrei Khalip)
