LONDON, June 6 (Reuters) - A British soldier was killed in southern Afghanistan on Wednesday while taking part in an operation against Taliban forces in the violent Helmand province, Britain's Ministry of Defence said. The death of the soldier, a member of the 1st battalion of the Worcestershire and Sherwood Foresters, brings to 59 the number of British troops to have died in the country since the U.S.-led invasion in 2001. Violence in Afghanistan has escalated in recent months after a traditional winter lull but a major offensive threatened by the Taliban has not materialised.