LONDON (Reuters) - British shares edged higher on Monday as commodities-related stocks shrugged off declines in copper and oil prices, although Mondi (>> Mondi Plc) fell on news of an anti-monopoly investigation.

Britain's blue-chip FTSE 100 index <.FTSE> was up 0.4 percent at 6,170.55 points by 0855 GMT, in line with the broader European market.

Miner Rio Tinto (>> Rio Tinto plc) led the gainers on the FTSE 100 index, up 2.4 percent, with analysts citing a supportive rise in the price of iron ore during the Asian session.

Miners Anglo American (>> Anglo American plc), Glencore (>> Glencore PLC) and BHP Billiton (>> BHP Billiton plc) shrugged off a decline in copper prices and concerns over Chinese demand, although some investors were expecting the sector to remain volatile.

"Given the fact that we probably are expecting to see a stronger U.S. dollar and weaker growth globally, then these basic metals will likely continue to be problematic and cut into profit margins," said Brenda Kelly, head analyst at London Capital Group.

Travel and leisure stocks also gained, with budget airline easyJet (>> easyJet plc) 0.8 percent higher after Irish-listed Ryanair Holdings (>> Ryanair Holdings plc) posted a jump in March traffic figures.

IAG (>> International Consolidated Airlns Grp SA) rose 1.8 percent and mid-cap Wizz Air (>> Wizz Air Holdings PLC) advanced 1.2 percent, with analysts citing a weaker oil price as supporting the sector.

Retailer Marks and Spencer was among the FTSE 100's top risers, up 1.4 percent after broker Peel Hunt upgraded its rating to "buy" from "hold" and raised its target price.

Paper and packaging company Mondi fell 2.5 percent after the Federal Antimonopoly service of the Russian Federation said it had initiated an investigation into Mondi Syktyvkar over the pricing of offset paper.

Mondi said it had not yet received any FAS notification.

Downgrades by investment bank Credit Suisse weighed on car insurer Admiral Group (>> Admiral Group plc) and Rolls-Royce Holdings (>> Rolls-Royce Holding PLC), which fell 1.3 percent and 0.7 percent respectively.

The FTSE 100 index is down just over 1 percent so far in 2016.

(Editing by Catherine Evans)

By Kit Rees