FTSE 100 index fluctuated between gains and losses on Thursday as government reported UK's trade deficit widened more than expected in February. Royal Dutch Shell tumbled 5% on news an oil sheen had been detected in the Gulf of Mexico. Aggreko jumped 2.4% after temperature-control supplier reported a strong growth in revenue. GKN climbed 5% after Credit Suisse upgraded the share from neutral to outperform. At the moment of writing FTSE 100 trades 0.2% or 11.75 points lower at 5,621.43.