* FTSE 100 flat at close
* GVC shares jump after MGM Resorts deal
* Vodafone rises after Elliott stake report
* Commodities stocks decline (Recasts, adds detail, updates prices at close)
By Kit Rees
LONDON, July 30 (Reuters) - Britain's top share index steadied on Monday as a jump in Vodafone and GVC's shares outweighed a broader decline among commodities-related sectors.
The blue-chip FTSE 100 .FTSE index ended the session flat in percentage terms at 7,700.85 points, slightly outperforming a broader decline among European stocks at the start of a week where central bank policymaking will be in focus.
Shares in GVC Holdings GVC.L were a bright spot, however, jumping 5.4 percent to the top of the index after the British gambling company agreed a joint venture with U.S. hotel and casino operator MGM Resorts International MGM.N to set up an online betting platform in the United States. shares hit a record high and were on track for their best day since mid-May.
"A 50/50 JV would enable GVC to benefit from a much larger profit pool in future, and any initial operating losses would likely be compensated for by future market share gains," analysts at Berenberg said in a note.
Vodafone VOD.L provided the biggest individual boost to the FTSE, its shares up 3.6 percent with traders citing a report that activist investor Elliott has taken new stake in the company. broadly, a decline across commodities-related stocks weighed on the FTSE. Heavyweight oil stocks BP BP.L was down 0.3 percent, while shares in miners Rio Tinto RIO.L , Glencore GLEN.L and Anglo American AAL.L all retreated 0.3-0.8 percent as the price of copper declined after economic data which may indicate slowing growth in top metals consumer China. MET/L
Earnings reports were the main focus among smaller stocks, with brickmaker Ibstock IBST.L the biggest mid-cap .FTMC faller. It was down more than 13 percent after the company said it expected first-half core earnings to fall and warned of lower-than-expected brick output in the second half of the year. HSX.L and Senior SNR.L were among the top gainers among mid caps, up 7.3 percent and 9.8 percent respectively after both companies gave updates.
Shares in underwriter Hiscox hit a record high after its first-half earnings beat expectations, boosted by higher premiums, while engineering firm Senior said its full-year guidance was unchanged.