London's FTSE 100 dropped below the 6,700 level for the first time in five months on Tuesday as ongoing worries about Greece and a sell-off on Chinese markets dampened risk appetite.The Footsie was down 0.63% at 6,668.31 by midday with the heavyweight mining sector providing a drag.The index has not finished below the 6,700 level since 20 January when it settled at 6,620.10.Market sentiment continues to be dominated by developments in Greece after an abrupt end to debt negotiations at the weekend with its lenders has rattled investors' nerves over recent days, as discussions collapsed after just 45 minutes on the back of disagreements over issues such as pension reforms and tax rates.Eurozone officials are now considering an emergency summit next weekend amid fears that Athens and its creditors will not reach a deal at a meeting of finance ministers on Thursday.Meanwhile, stocks in Shanghai plunged again on Tuesday due to weakness in the financial sector as regulators tightened margin lending regulations and investors showed concerns ahead of a barrage of upcoming IPOs.As expected, data showed that the UK exited deflation in May with consumer prices rising 0.1% year-on-year after a 0.1% decline in April.Defensives gain, miners fallA reduction in risk appetite benefitted stocks in defensive sectors such as tobacco and pharmaceuticals. British American Tobacco, Imperial Tobacco and Glaxosmithkline were all edging higher in London.British American Tobacco and Imperial Tobacco were boosted after Credit Suisse reinstated coverage on both stocks at 'outperform'. The broker applauded BAT's "consistent track record" and showed optimism about Imperial's recent purchase of Reynolds assets.Meanwhile, GSK was up on rumours it could become the latest takeover target in the industry. According to the Daily Mail, market participants are speculating that the company may face an approach from Switzerland's Roche or US company Johnson & Johnson at about 1900p per share.Mining stocks were among the worst performers, with Rio Tinto, Randgold and Antofagasta all in negative territory.Royal Mail was in the red after Ofcom announced a fundamental review to make sure the postal operator faces adequate competition following Whistl's withdrawal from the direct-delivery letters market.Leisure group Whitbread fell after missing forecasts slightly with a first-quarter update. Like-for-like sales rose by 4.3% as a flat performance in the restaurants division limited growth.Industrial equipment hire company Ashtead underwhelmed with full-year results. The group posted a 33% rise in full-year pre-tax profit to £473.8m on strong US and UK markets. Market MoverstechMARK 3,136.10 -0.49%FTSE 100 6,668.31 -0.63%FTSE 250 17,619.57 -0.62%FTSE 100 - RisersBritish American Tobacco (BATS) 3,501.50p +2.64%Imperial Tobacco Group (IMT) 3,223.00p +1.51%GlaxoSmithKline (GSK) 1,359.50p +0.63%Vodafone Group (VOD) 232.05p +0.37%Centrica (CNA) 262.90p +0.34%Aberdeen Asset Management (ADN) 408.90p +0.25%National Grid (NG.) 850.10p +0.18%Barratt Developments (BDEV) 597.00p +0.17%SABMiller (SAB) 3,304.50p +0.15%FTSE 100 - FallersInternational Consolidated Airlines Group SA (CDI) (IAG) 492.00p -3.24%Ashtead Group (AHT) 1,100.00p -2.40%TUI AG Reg Shs (DI) (TUI) 1,149.00p -1.88%BT Group (BT.A) 444.20p -1.85%Royal Mail (RMG) 495.70p -1.84%Standard Chartered (STAN) 1,019.50p -1.78%Randgold Resources Ltd. (RRS) 4,545.00p -1.75%Fresnillo (FRES) 721.00p -1.70%CRH (CRH) 1,799.00p -1.69%Antofagasta (ANTO) 716.00p -1.65%FTSE 250 - RisersLadbrokes (LAD) 121.30p +3.68%Tullett Prebon (TLPR) 378.60p +1.88%Euromoney Institutional Investor (ERM) 1,171.00p +1.83%Pets at Home Group (PETS) 277.40p +1.35%Zoopla Property Group (WI) (ZPLA) 265.60p +0.99%Greggs (GRG) 1,180.00p +0.85%Ted Baker (TED) 2,867.00p +0.70%Bwin.party Digital Entertainment (BPTY) 97.80p +0.67%Electra Private Equity (ELTA) 3,199.00p +0.66%Clarkson (CKN) 2,575.00p +0.66%FTSE 250 - FallersKaz Minerals (KAZ) 233.50p -4.30%Ophir Energy (OPHR) 118.10p -3.12%Ocado Group (OCDO) 370.70p -2.98%Fidelity China Special Situations (FCSS) 163.50p -2.97%Bank of Georgia Holdings (BGEO) 1,808.00p -2.95%Thomas Cook Group (TCG) 135.60p -2.93%Vesuvius (VSVS) 392.00p -2.54%Lonmin (LMI) 126.60p -2.39%Allied Minds (ALM) 549.00p -2.23%Cairn Energy (CNE) 180.60p -2.17%