(ShareCast News) - The FTSE 250 fell 1.6%, led by a sharp drop in Spire Healthcare shares. The index of mid-cap stocks was down 226.5 points to 17,012.Spire was hit by a warning that second-half revenues from the the UK's National Health Service would be flat this year compared with previous guidance of low single-digit growth.The warning came after the private healthcare group posted a profit of £30.8m compared with a loss of £7.8m in the same period last year, as revenue rose 7.8% to £449.8m with growth across all payor groups.Brown (N.) Group fell 6.53% after BNP Paribas cut its price target to 300p from 320p. The broker has an "underperform" rating on the stock.Among the risers were precious metals producers Lonmin, and Polymetal up 5% and 3.45% respectively as investors looked for safe havens. RisersLonmin (LMI) 37.07p +5.10%Polymetal International (POLY) 482.60p +3.45%Wood Group (John) (WG.) 577.00p +2.67%SIG (SHI) 190.50p +2.53%PayPoint (PAY) 1,013.00p +2.32%Acacia Mining (ACA) 265.50p +2.04%Telecom Plus (TEP) 1,104.00p +2.03%AO World (AO.) 122.40p +1.16%Premier Farnell (PFL) 129.10p +1.02%Tullow Oil (TLW) 205.30p +0.98%FallersSpire Healthcare Group (SPI) 348.20p -13.30%OneSavings Bank (OSB) 300.20p -6.77%Brown (N.) Group (BWNG) 300.70p -6.53%Premier Oil (PMO) 104.90p -5.92%CLS Holdings (CLI) 1,851.00p -5.08%Ted Baker (TED) 3,144.00p -4.47%Bank of Georgia Holdings (BGEO) 1,749.00p -4.43%Fidelity China Special Situations (FCSS) 116.30p -4.36%Worldwide Healthcare Trust (WWH) 1,849.00p -4.20%Betfair Group (BET) 2,642.00p -3.75%