London midday: Stocks mixed after stream of updates

The leading share index is flitting between red and blue amid differing receptions for today's stream of updates.Investors in Admiral are feeling mutinous despite pre-tax profits growing by 27%. However, according to a Thomson Reuters poll, the result was a slight miss.Miner BHP Billiton is higher after seeing a 35.9% jump in revenue in the year ended June. The final dividend was upped by 22%.Outsourcing firm Serco fell despite saying it overcame UK and US headwinds to deliver a 12.2% rise in adjusted pre-tax profit, driven by its international portfolio. ENRC, Catlin and WS Atkins were also among the fallers after going ex-dividend.On the rise, however, were the financials, with Man Group, RBS, Lloyds, Barclays and ICAP posting decent gains.Advertising and marketing group WPP, led by chief executive Sir Martin Sorrell, rose saying the "post-Lehman bounce-back" has continued as it posted pre-tax profit growth of 37% on sales that grew 6.1% in the six months to 30 June.Africa-focused oil giant Tullow Oil was firmer after it reported a huge surge in sales and profits in the six months ended 30 June, helped by increased production from the Jubilee field off Ghana and higher commodity prices.Tesco was edging higher after an announcement that Andrew Higginson, chief executive of Retailing Services at the supermarket giant, is heading for the check-out counter next year.The economic divide between London and the rest of the UK appears even to extend to the student accommodation sector, judging by Unite Group's half year results. The shares are sharply higher after it said that in the six months to 30 June, the company's diluted net asset value climbed to 310p a share from 295p at the beginning of the year. The value of the group's stabilised property portfolio grew by 2.1%, with rental growth in the first six months delivering £15m of net valuation uplift. Speciality plastic and fibre products supplier Filtrona said it well placed for further growth despite economic uncertainty as it posted a rise in revenues and profits. In the six months to 30 June, revenue jumped to £268.6m from £247.6m over the same period the previous year, while pre-tax profits rose to £39.5m from £34.6m. The dividend was raised by 10% to 3.3p from 3p. Profits at British building firm Carillion were up 10% in the first half of the year, reaching £72.5m. However, including one-off acquisition costs of £28m the company saw profits drop by 35%. Chairman, Philip Rogerson, said the builder expected to deliver full-year earnings growth in line with market expectations. FTSE 100 - RisersTullow Oil (TLW) 1,000.00p +5.65%Man Group (EMG) 206.50p +5.30%WPP (WPP) 609.00p +5.00%ARM Holdings (ARM) 526.50p +2.43%G4S (GFS) 270.30p +2.23%Xstrata (XTA) 957.40p +2.05%Cairn Energy (CNE) 299.50p +1.91%Fresnillo (FRES) 1,921.00p +1.53%ICAP (IAP) 433.70p +1.50%Carnival (CCL) 1,776.00p +1.49%FTSE 100 - FallersAdmiral Group (ADM) 1,399.00p -8.86%Serco Group (SRP) 511.50p -3.85%Hargreaves Lansdown (HL.) 414.30p -3.56%Essar Energy (ESSR) 247.00p -3.33%Diageo (DGE) 1,095.00p -2.41%Barclays (BARC) 142.50p -2.03%British American Tobacco (BATS) 2,688.00p -1.47%Unilever (ULVR) 2,012.00p -1.47%Amec (AMEC) 910.50p -1.09%Royal Dutch Shell 'A' (RDSA) 1,933.00p -1.05%FTSE 250 - RisersUnite Group (UTG) 165.80p +8.44%Filtrona PLC (FLTR) 332.00p +5.43%Carillion (CLLN) 327.00p +5.04%Micro Focus International Plc (MCRO) 282.60p +3.55%Michael Page International (MPI) 375.00p +3.45%Kenmare Resources (KMR) 41.55p +3.20%Keller Group (KLR) 357.10p +3.09%Telecom Plus (TEP) 653.50p +2.91%Dignity (DTY) 748.00p +2.89%Carpetright (CPR) 527.50p +2.73%FTSE 250 - FallersPremier Foods (PFD) 13.05p -5.57%William Hill (WMH) 212.60p -2.97%Atkins (WS) (ATK) 524.50p -2.78%Amlin (AML) 300.50p -2.56%Supergroup (SGP) 876.00p -2.50%Charter International (CHTR) 728.50p -2.48%Enterprise Inns (ETI) 38.28p -2.42%Ladbrokes (LAD) 121.50p -2.17%Beazley (BEZ) 111.80p -2.02%SThree (STHR) 234.60p -2.01%