UK stocks dropped on Thursday as election uncertainty and a poorly-received update from blue chip supermarket chain Morrisons dampened sentiment.The FTSE 100 was down 0.8% at 6,878.01 early on, with Morrisons leading the decline as sales trends worsened in its first quarter. Stocks in the resources sectors were also trading lower as risk appetite weakened.Analyst Craig Erlam from Oanda said the polls have barely changed in recent months "and still show the Conservatives and Labour neck and neck with around a third of the votes each meaning both will be a long way from securing a majority".??He said: "This creates a lot of uncertainty that could weigh on the markets today."Investors will also likely be acting cautiously ahead of a number of other risk events for global markets, such as the all-important US jobs report on Friday and ongoing Greek negotiations.Morrisons drops, Telecity surgesThe sales decline at Morrisons, the UK's fourth-largest supermarket chain, worsened in its first quarter with like-for-like sales excluding fuel down 2.9%. This compared with a lesser 2.6% fall in the fourth quarter of the previous financial year. Results were not as bad as feared, but that didn't stop the stock from dropping over 7% early on.Mining and oil stocks were also providing a drag on the FTSE with BP, Anglo American, Glencore, BHP Billiton and Shell trading in the red.FTSE 250 datacentres group Telecity jumped 20% after receiving a takeover offer from Equinix at 1145p per share in cash and equity. This bid, at a 27% premium to the closing price on Wednesday, values Telecity at £2.32bn.BT edged higher after the telecoms giant's annual profits beat City forecasts as it added a record number of new broadband customers in the fourth quarter.Insurance group RSA impressed investors with a positive start to the year as underlying premium income returned to modest growth, though reported results were dented by the strength of the pound.Ladbrokes declined on the news that its chairman Peter Erskine has stepped down, five months after chief executive Richard Glynn left the bookmaker.Easyjet was higher despite saying that annual traffic growth slowed sharply in April as the company was forced to cancel hundreds more flights than last year,Market MoverstechMARK 3,184.40 -0.30%FTSE 100 6,878.01 -0.80%FTSE 250 17,331.54 -0.46%FTSE 100 - RisersRSA Insurance Group (RSA) 427.50p +2.27%Antofagasta (ANTO) 793.00p +1.34%easyJet (EZJ) 1,793.00p +1.13%Carnival (CCL) 2,927.00p +0.83%Aviva (AV.) 517.00p +0.68%Randgold Resources Ltd. (RRS) 4,935.00p +0.43%Legal & General Group (LGEN) 260.20p +0.42%Pearson (PSON) 1,293.00p +0.31%Standard Life (SL.) 462.30p +0.24%BT Group (BT.A) 455.30p +0.22%FTSE 100 - FallersMorrison (Wm) Supermarkets (MRW) 175.90p -7.08%Admiral Group (ADM) 1,498.00p -3.35%G4S (GFS) 282.30p -2.99%GlaxoSmithKline (GSK) 1,481.00p -2.21%BP (BP.) 463.30p -2.11%Hargreaves Lansdown (HL.) 1,153.00p -1.79%Anglo American (AAL) 1,134.00p -1.69%Sage Group (SGE) 527.50p -1.59%Persimmon (PSN) 1,612.00p -1.59%Babcock International Group (BAB) 984.00p -1.55%FTSE 250 - RisersTelecity Group (TCY) 1,080.00p +20.07%PayPoint (PAY) 829.50p +3.75%Genus (GNS) 1,312.00p +2.98%Diploma (DPLM) 780.50p +2.90%FirstGroup (FGP) 102.70p +2.29%Riverstone Energy Limited (RSE) 1,063.00p +1.92%Man Group (EMG) 176.10p +1.85%Indivior (INDV) 225.10p +1.81%esure Group (ESUR) 232.90p +1.57%Just Eat (JE.) 484.20p +1.47%FTSE 250 - FallersAllied Minds (ALM) 581.00p -6.29%Ophir Energy (OPHR) 138.00p -5.15%Millennium & Copthorne Hotels (MLC) 575.00p -4.25%Ted Baker (TED) 2,846.00p -3.92%Morgan Advanced Materials (MGAM) 323.20p -3.58%Soco International (SIA) 190.70p -3.54%Fidelity China Special Situations (FCSS) 159.00p -3.05%Henderson Group (HGG) 270.20p -2.77%Home Retail Group (HOME) 158.80p -2.58%Acacia Mining (ACA) 295.00p -2.58%