By Jack Barnett London’s FTSE 100 was dragged lower today by investors ditching UK banks on fears they will be hit by a windfall tax by new chancellor Jeremy Hunt. The capital’s premier index fell 0.17 per cent to 6,924.99 points, while the domestically-focused mid-cap FTSE 250 index, which is more aligned with the health of the UK economy, tumbled 1.61 per cent to 17,247.55 points. Hunt is thought to be eyeing reversing plans to drop the bank surcharge to three per cent from eight per cent to prevent them being taxed too punitively after the corporation tax rise next April. A treasury spokesp…