UK stocks slid sharply on Monday after Greece shut its banks and called a public vote to decide the fate of its future within the Eurozone.With just three stocks on the FTSE 100 in positive territory, the UK index was down 1.63% at 6,643.30 by midday. The index had dropped to a low of 6,598.64 early on - it has not closed below the 6,600 mark since mid-January.Over the weekend, Greece's government called a referendum on the bailout terms proposed by its international creditors, while imposing capital controls on its banks to defend liquidity. Athens said banks will remain closed until after the public vote on 5 July and account holders would only be able to withdraw €60 a day.After talks with lenders failed at the weekend, Greece has now effectively run out of time to secure funding to help repay €1.6bn to the IMF by Tuesday, the same day that its current bailout agreement expires."It currently feels like the relative calm before the potential storm tomorrow as Greece gets ready to almost inevitably fail to meet its IMF payment," said Spreadex analyst Connor Campbell.European markets were also tracking a sell-off in Asia overnight as Chinese stocks entered into bear territory, having plunged over 20% in around two weeks.Despite an interest-rate cut by the People's Bank of China - its fourth since November - the Shanghai Composite plunged 3.34% to 4,053 and the Hang Seng index tumbled 2.61% to 25,967, the latter's worst one-day sell-off in over a year.Airline stocks slideTravel tour operators TUI and Thomas Cook dropped sharply as investors expressed concerns about Greece and the impact of potential social unrest on the travel market.Wider concerns about the disruption on tourism from recent terrorist attacks in Paris and Tunisia were also likely dampening sentiment, pulling shares of airline peers IAG and Easyjet lower.IAG in particular was registering heavy losses as EU regulators continued to review its proposed takeover of Irish carrier Aer Lingus amid competition concerns.Stocks in the financial sectors such as Hargreaves Lansdown, Aberdeen Asset Management and Henderson Group were falling as market volatility increased across Europe.FTSE 100-listed drinks bottler Coca-Cola HBC, which has a secondary listing in Athens, was also suffering heavy losses.Precious metal miners Randgold and Fresnillo were two of three stocks making gains on the Footise as investors sought out safe-haven investments such as gold.Market MoverstechMARK 3,124.32 -1.42%FTSE 100 6,643.30 -1.63%FTSE 250 17,590.65 -1.30%FTSE 100 - RisersRandgold Resources Ltd. (RRS) 4,431.00p +1.30%Intertek Group (ITRK) 2,437.00p +0.62%Fresnillo (FRES) 701.00p +0.43%FTSE 100 - FallersTUI AG Reg Shs (DI) (TUI) 1,038.00p -6.74%International Consolidated Airlines Group SA (CDI) (IAG) 497.90p -3.23%GKN (GKN) 337.10p -2.91%Standard Chartered (STAN) 1,026.00p -2.75%Standard Life (SL.) 463.90p -2.58%Dixons Carphone (DC.) 453.80p -2.56%SABMiller (SAB) 3,337.00p -2.53%CRH (CRH) 1,812.00p -2.53%Unilever (ULVR) 2,763.00p -2.44%Coca-Cola HBC AG (CDI) (CCH) 1,395.00p -2.38%FTSE 250 - RisersGrainger (GRI) 229.70p +2.77%Serco Group (SRP) 121.90p +1.58%Ocado Group (OCDO) 429.50p +0.89%Centamin (DI) (CEY) 63.00p +0.72%Aggreko (AGK) 1,457.00p +0.55%OneSavings Bank (OSB) 317.00p +0.54%Tritax Big Box Reit (BBOX) 114.00p +0.53%Northgate (NTG) 619.00p +0.49%Greggs (GRG) 1,211.00p +0.33%International Public Partnerships Ltd. (INPP) 135.90p +0.30%FTSE 250 - FallersHenderson Group (HGG) 262.80p -4.58%Hunting (HTG) 614.50p -3.98%Thomas Cook Group (TCG) 138.90p -3.68%Bodycote (BOY) 692.00p -3.49%Evraz (EVR) 123.50p -3.29%FirstGroup (FGP) 119.50p -3.24%Euromoney Institutional Investor (ERM) 1,168.00p -3.23%Bank of Georgia Holdings (BGEO) 1,931.00p -3.06%Man Group (EMG) 159.90p -3.03%Rathbone Brothers (RAT) 2,104.00p -2.95%