UK stocks dropped over one per cent to a three-month low on Monday as concerns about a potential Greek exit from the Eurozone hammered market sentiment.The FTSE 100 fell 1.1% to 6,710.52, with heavyweights Easyjet and Standard Chartered among the worst performers by the end of trade. Just four stocks on the blue-chip index finished in positive territory.The index has not closed below this level since 10 March when it settled at 6,702.84.An abrupt end to debt talks on Sunday night in Brussels between Greece and its lenders rattled investors' nerves across Europe, with Athens Stock Exchange in particular dropping nearly 5%.Discussions ended after just 45 minutes on the back of disagreements over issues such as pension reforms and tax rates. A spokesman from the European Commission said there was still a "significant gap" between the two sides.Time is now running out for Athens as it faces a €1.6bn debt repayment to the International Monetary Fund at the end of the month.ECB president Mario Draghi said the "ball lies squarely in the camp of the Greek government" and called for a "strong and comprehensive agreement" between Athens and its creditors. "We need this very soon," he said.The market's attention was turning to a Eurogroup meeting on Thursday which could, in the absence of a deal, result in the ECB cutting all emergency funding to Greece's banks, according to reports.In the meantime, investors were also showing caution ahead of Wednesday's policy meeting at the Federal Reserve, which is expected to offer some indications on whether a rate hike could be on the cards in September.Travel stocks lead the declineShares in budget airline Easyjet fell after RBC Capital Markets downgraded the stock to 'underperform' from 'outperform' and slashed its price target to 1,500p from 2,000p, noting that its positive outlook for summer has proved incorrect. "As summer is key, we see few positive catalysts until mid-2016, while easyJet faces a winter squeeze," said RBC.Airline conglomerate IAG was also out of favour, along with cruise operator Carnival and travel tour operators TUI and Thomas Cook.Thomas Cook also declined after announcing a new joint venture with shareholder Fosun International with the aim of developing domestic, inbound and outbound tourism activities for the Chinese market.Shares in Standard Chartered dropped after Jefferies cut its price target and warned that the company may cut its dividend to bolster capital.Meanwhile, HSBC downgraded Tullett Prebon to 'hold' from 'buy' on valuation grounds, causing shares in the interdealer broker to sink.Housebuilding stocks were also registering losses, including Taylor Wimpey, Barratt Developments and Crest Nicholson.Market MoverstechMARK 3,151.46 -1.17%FTSE 100 6,710.52 -1.10%FTSE 250 17,728.73 -1.23%FTSE 100 - RisersRandgold Resources Ltd. (RRS) 4,626.00p +0.41%Tesco (TSCO) 214.00p +0.14%Compass Group (CPG) 1,115.00p +0.09%BG Group (BG.) 1,088.50p +0.05%FTSE 100 - FallersTaylor Wimpey (TW.) 183.40p -2.86%Imperial Tobacco Group (IMT) 3,175.00p -2.85%TUI AG Reg Shs (DI) (TUI) 1,171.00p -2.82%Mondi (MNDI) 1,362.00p -2.71%G4S (GFS) 281.30p -2.70%Rolls-Royce Holdings (RR.) 945.00p -2.58%Hargreaves Lansdown (HL.) 1,210.00p -2.50%GKN (GKN) 356.30p -2.46%Barratt Developments (BDEV) 596.00p -2.46%Standard Chartered (STAN) 1,038.00p -2.44%FTSE 250 - RisersSoco International (SIA) 188.10p +5.67%Poundland Group (PLND) 308.30p +3.04%Aveva Group (AVV) 1,957.00p +2.03%Supergroup (SGP) 1,192.00p +1.88%UK Commercial Property Trust (UKCM) 89.85p +1.64%Zoopla Property Group (WI) (ZPLA) 263.00p +1.15%Brown (N.) Group (BWNG) 347.80p +1.13%Polymetal International (POLY) 545.00p +1.11%Countrywide (CWD) 580.00p +0.87%Just Retirement Group (JRG) 179.80p +0.84%FTSE 250 - FallersTullett Prebon (TLPR) 371.60p -7.95%Allied Minds (ALM) 561.50p -5.07%Morgan Advanced Materials (MGAM) 330.60p -4.51%Jimmy Choo (CHOO) 158.00p -3.72%Spire Healthcare Group (SPI) 331.00p -3.70%Ashmore Group (ASHM) 305.10p -3.54%Centamin (DI) (CEY) 63.90p -3.47%Crest Nicholson Holdings (CRST) 544.50p -3.20%Fisher (James) & Sons (FSJ) 1,324.00p -3.00%RPS Group (RPS) 226.50p -3.00%