(Alliance News) - US-China trade optimism in markets gave way to doubts over the outlook for relations between the two, leading the FTSE 100 to slump nearly 70 points at midday on Wednesday.London's blue-chip index was further hampered by miners following some weak industrial data from China, which offset a decent session for insurer Admiral in the wake of a solid set of interim results.The FTSE 100 was down 67.17 points, or 0.9%, at 7,183.73, while the FTSE 250 was down 141.79 points, or 0.8%, at 18,866.39. The AIM All-Share was down 0.5% at 873.04.The Cboe UK 100 index was down 1.0% at 12,175.71. The Cboe UK 250 was down 0.7% at 16,785.82, while the Cboe UK Small Companies was down 0.1% at 10,901.89."Yesterday's surprise suspension of some China tariffs by the US certainly had the required effect in driving stock markets higher, but does it really change the overarching narrative of a US administration and China that continue to be at odds over trade, as well as intellectual property?" questioned Michael Hewson at CMC Markets. He added: "Investors need to remember that while some of the more consumer sensitive tariffs have been delayed until the 15th December, and some dropped completely, the ante is still higher than it was before President Trump announced the tariffs increases, at the beginning of the month."With Tuesday's cheerier mood fading, stocks in the US are pointed towards a downbeat start on Wednesday. The Dow Jones and S&P 500 are both seen down 0.6%, while the Nasdaq is called 0.7% lower.On Tuesday, the Dow Jones and S&P 500 had both closed 1.5% higher, while the Nasdaq had surged 2.0%.As well as doubts over the latest US-China trade move, the FTSE 100 was kept in check by a stronger pound.Sterling was quoted at USD1.2091 at midday, versus USD1.2062 late Tuesday.This was after UK inflation unexpectedly rose above the Bank of England's 2% target in July.The consumer price index rose 2.1% in July on a year before, accelerating from the 2.0% annual increase seen in June. This surpassed consensus, as cited by FXStreet, for consumer price growth to ease to 1.9%.With July's inflationary surge, ING said it could be "too early" to be talking of interest rate cuts. "The domestic inflation backdrop suggests that UK rate cuts are unlikely to be forthcoming in the near-term, although as ever, everything depends on Brexit and where things stand after 31 October," ING added.While the pound firmed against the dollar, the euro softened after confirmation Germany's economy shrank in the second quarter. Eurostat showed eurozone gross domestic product growth slowed in the second quarter, with Germany weighing on the bloc.The eurozone economy grew 0.2% in the three months to June, with the wider EU28 also registering a 0.2% rise quarter-on-quarter. In the first three months of the year, the eurozone economy had grown 0.4% and the EU28 by 0.5% from the fourth quarter of 2018. Based on sequential GDP growth, Germany was the worst performer in the eurozone.Earlier on Wednesday, Destatis showed Germany's economy shrank 0.1% quarter-on-quarter, reversing the 0.4% growth registered in the three months to March.The euro was quoted at USD1.1182 at midday, from USD1.1190 late Tuesday.In mainland Europe, the CAC 40 in Paris was down 1.4% while the DAX 30 in Frankfurt sank 1.5%.Miners were among the worst performers in London following some weak data from China, with Anglo American down 2.6%, Glencore down 1.9% and Antofagasta down 1.4%.China's economy showed further signs of strain in July with output at its factories falling to its lowest level in 17 years, official data showed. Industrial output increased 4.8% on-year in July, down from 6.3% in June and marking the weakest pace since 2002.At the same time, the data showed retail sales - which have long been a bright spot for the economy - slowed to a 7.6% rise last month, sharply down from 9.8% in June. Fashion house Burberry, reliant on the fast-growing Chinese luxury consumer market, was down 1.8% at midday.All this was offsetting a 3.1% rise for insurer Admiral, which posted a solid set of interim results despite a hit from the Ogden rate.Net revenue rose to GBP647.1 million from GBP598.1 million, while pretax profit increased 4% to GBP218.2 million from GBP210.7 million. The insurer declared an interim dividend of 63.0p per share, up 5% year-on-year, comprising a normal dividend of 41.8p and a special dividend of 21.2p."If it's a can't-put-down, read-in-one-go page-turner that you're after, then I'm afraid our half-year results don't fit the bill. Frankly, they are a bit dull. Turnover up mid-single digits, profit up low-single digits. Hardly 'hold the front page'," said Chief Executive David Stevens.He continued: "However, for dedicated aficionados who look behind the headlines, there's some reward for reading on. Profit growth, even if modest, is more exciting considering the GBP33 million Ogden headwind."The Ogden rate is a calculation used by courts to work out how much insurance companies need to pay out in the event of life-changing injuries to customers, taking into account the likely return from the investment of such awards.The higher the rate, the better the outcome is for insurers. The Ogden discount rate was changed to minus 0.25%, effective August 5, from minus 0.75%. However, Admiral had been expecting a rate of 0%.The mid-cap FTSE 250 was faring little better than its blue-chip counterpart as constituent Sports Direct slid 10%.The sportswear retailer confirmed that auditor Grant Thornton does not intend to seek reappointment at Sports Direct's annual general meeting on September 11."A further announcement will be made in due course," Sports Direct said in a statement Wednesday. Grant Thornton came to the decision "following a review of its client portfolio", the retailer - which also owns troubled department store House of Fraser - said.Meanwhile, well-received earnings reports drove Balfour Beatty and Avast to the top of the index. Balfour Beatty shares surged 7.9% as its boosted its interim dividend by almost a third amid profit growth.Revenue, which includes its income from joint ventures, rose by 1% to GBP3.88 billion in the six months to June 28 from GBP3.84 billion a year before. Pretax profit jumped by 26% to GBP63.0 million from GBP50.0 million and on an underlying basis by 14% to GBP64.0 million from GBP56.0 million. The construction firm raised its interim dividend by 31% to 2.1 pence per share from 1.6p.Cybersecurity firm Avast was up 5.5% as it anticipated like-for-like revenue to increase by high single-digits in 2019 following a strong performance in the first half. The cybersecurity provider reported pretax profit for the six months to the end of June of USD186.0 million, up 14% compared to USD162.7 million a year earlier, as revenue rose 5.8% to USD426.8 million from USD403.3 million. On a like-for-like basis, the FTSE 250-listed company said its adjusted billings increased year-on-year by 13% at constant currency, and 9.2% at actual rates to USD454.6 million.