LONDON, April 30 : Renewed risk aversion swept global equity and bond markets on Thursday and oil surged to a four-year high on worries that the Iran war could worsen, before what could be difficult European Central Bank and Bank of England meetings. The rise of global oil benchmark Brent crude futures to more than $126 before falling back, and an early drop in European stocks [.EU], reflected concerns that a prolonged conflict in the Middle East could choke oil supplies for months. A hawkish