The FTSE 100 and European markets followed Asian indices lower on Tuesday morning, as traders grapple with a fall in oil prices and a mixed day on Wall Street on Monday. The FTSE (^FTSE) was 31 points, or 0.4%, lower at the opening bell in London. At the open Prudential (PRU.L), DS Smith (SMDS.L) and JD Sports (JD.L) were among the top losers. The DAX (^GDAXI) also lost 0.2% and the CAC (^FCHI) fell 0.5%. Meanwhile, the pan-European STOXX 600 (^STOXX) was 0.3% lower. Brent crude (BZ=F) futures fell around 0.7% as traders fret about a prolonged environment of high interest rates and ongoing demand. The shaky start also comes following a spat in London over competition in the payments market. This morning the Payments Systems Regulator outlined plans to crack down on merchant fees. It said there was "little evidence" that the likes of Visa (V) and Mastercard (MA) could justify the rise in fees and there is insufficient competition in the market to stop higher prices. Mastercard says it disagrees. It said: "The payments industry has never been more competitive, which is reflected in the wide choice of payment options available to British consumers and businesses." Follow along...