Police have launched an investigation after a 13-year-old boy was stabbed outside a McDonald's in Birmingham city centre. Emergency services rushed to the scene after the teenager was attacked in front of horrified shoppers and commuters at 4pm on Wednesday (18/1). The boy was taken to hospital for treatment to 'potentially life-changing injuries' as cops swarmed the city centre and hunted for the knifeman. Officers cordoned off a ramp leading up to Birmingham's New Street station and Grand Central, outside a McDonald's restaurant. West Midlands Police said patrols had been stepped up in the area and urged any witnesses to get in touch. A force spokesman said: "We were called after a teenage boy was stabbed in Stephenson Place in the city centre, shortly after 4.30pm on Wednesday. "The 13-year-old boy has been taken to hospital with potentially life-changing injuries. "We had more officers in the area last night to offer reassurance to the public. "People with information should contact us via Live Chat on our website or by calling 101 quoting log number 2795 of 18 January." A spokeswoman from West Midlands Ambulance Service said: "We were called at 4.41pm to an incident on Stephenson Place, Birmingham along with police colleagues. "An ambulance, paramedic officer, a MERIT trauma doctor and critical care paramedic responded to the scene."