The FTSE 100 edged higher on Thursday after a strong reading of UK construction activity, though gains were limited amid ongoing uncertainty in Greece and ahead of a closely-followed report on the US labour market.The UK construction sector bounced back in June, according to a higher-than-expected reading of the purchasing managers' index from Markit/CIPS. June's PMI reading came in at 58.1, higher than the 56.5 consensus forecast and up from 55.9 from May.The data lifted the Footsie up 0.23% to 6,623.86 by midday."A better-than-expected UK construction PMI helped take the FTSE higher than its European peers this Thursday morning; however with little else on the horizon for the UK index, the FTSE is likely to be at the whim of the still-troubled Eurozone or the super-stacked afternoon of US data," said Spreadex analyst Connor Campbell.Investors were keeping one eye on the ongoing Greek debt saga on Thursday after the government promised to push ahead with a planned referendum on a bailout deal this Sunday.After showing signs of conceding ground and offering to meet most of the demands from last week's funding proposal, Greek Prime Minister Alexis Tsipras said the planned 5 July vote would still go ahead and reiterated his call on the public to say 'no'.Meanwhile, the country's finance minister Yanis Varoufakis said in an interview with Bloomberg TV that he would resign if the public votes 'yes' on Sunday. Polls on Thursday morning suggested that the referendum result was too close to call.European leaders have now broken off talks about a new deal and said they would not hold more discussions until after the referendum.Looking ahead, the US non-farm payrolls figure for June - scheduled one day earlier than normal due the weekend's Fourth of July celebrations - will be released at 13:30, along with a barrage of other labour-market data such as the unemployment rate, average hourly earnings, and weekly jobless claims.Analysts expect the Labor Department to report that 230,000 payrolls were added in the US economy last month, down sharply from the forecast-beating 280,000 that were registered for May, the highest since December 2014. The unemployment rate is estimated to tick down further to 5.4% from 5.5%.Ex-div stocks provide a dragA number of blue chips were trading in the red after going ex-dividend, including Compass, Babcock, British Land, Burberry, Coca-Cola HBC and Royal Mail.Dixons Carphone rose strongly after entering into an agreement with Sprint Corp to open and manage a significant number of Sprint-branded stores in the US.Housebuilder Persimmon slipped despite a solid first-half report with revenues increasing by 12%, as investors booked profits with the stock close to record highs.Product testing outfit Intertek was out of favour Jefferies lowered its stance on the shares to 'underperform' and cut its target price from 2,400p to 2,100p.Outsourcer Serco was extending gains made on Wednesday following a strong first-half trading update, as Numis raised its rating on the stock to 'hold'.?Market MoverstechMARK 3,131.34 +0.08%FTSE 100 6,623.86 +0.23%FTSE 250 17,684.75 -0.18%FTSE 100 - RisersBHP Billiton (BLT) 1,285.00p +1.98%BP (BP.) 426.55p +1.77%United Utilities Group (UU.) 907.00p +1.68%Dixons Carphone (DC.) 466.00p +1.57%SSE (SSE) 1,561.00p +1.50%Centrica (CNA) 267.70p +1.48%National Grid (NG.) 829.40p +1.43%RSA Insurance Group (RSA) 408.30p +1.37%Rio Tinto (RIO) 2,656.50p +1.35%Anglo American (AAL) 921.50p +1.25%FTSE 100 - FallersHargreaves Lansdown (HL.) 1,135.00p -2.91%Ashtead Group (AHT) 1,073.00p -2.54%Royal Mail (RMG) 505.00p -2.42%Burberry Group (BRBY) 1,554.00p -2.33%ARM Holdings (ARM) 1,039.00p -2.26%Intertek Group (ITRK) 2,409.00p -2.15%International Consolidated Airlines Group SA (CDI) (IAG) 493.30p -1.83%Coca-Cola HBC AG (CDI) (CCH) 1,355.00p -1.81%ITV (ITV) 262.90p -1.57%G4S (GFS) 268.20p -1.54%FTSE 250 - RisersSerco Group (SRP) 130.70p +10.76%BTG (BTG) 670.00p +6.69%Jimmy Choo (CHOO) 165.90p +5.80%Entertainment One Limited (ETO) 373.80p +5.00%Ocado Group (OCDO) 465.30p +4.35%AA (AA.) 386.40p +4.24%Supergroup (SGP) 1,279.00p +4.07%Cineworld Group (CINE) 479.40p +4.01%Drax Group (DRX) 361.60p +3.85%esure Group (ESUR) 263.40p +3.70%FTSE 250 - FallersZoopla Property Group (WI) (ZPLA) 265.00p -4.68%Evraz (EVR) 117.60p -4.55%ICAP (IAP) 508.50p -3.97%Lonmin (LMI) 107.50p -3.93%Acacia Mining (ACA) 291.30p -3.51%Hunting (HTG) 591.00p -3.11%Foxtons Group (FOXT) 230.20p -2.83%Homeserve (HSV) 427.90p -2.82%AO World (AO.) 141.20p -2.42%Crest Nicholson Holdings (CRST) 548.00p -2.40%