Centrica tops the sector for the sixth consecutive year. First-half revenues were up 14% to £13.7bn, but political heat over rising bills caused boss Sam Laidlaw to forgo his bonus in November and warn that full-year profits would be flat. All eyes will be on National Grid this winter as it develops emergency measures to prevent 1970s-style blackouts. Scottish & Southern Energy comes third despite mixed fortunes: it was fined £10.5m for mis-selling on the doorstep and its 8.2% price hike has angered customers. Electricity generator Drax Group has edged up to fourth - earlier this year, it became the first company to receive funding from the Treasury's UK Guarantees Scheme to convert its coal plant to run on biomass.