Hi, I am an indian passport holder. I have a spain national visa (issued for students)valid for 5 months and I am going back home to india but my flight is thro

Hi, I am an indian passport holder. I have a spain national visa (issued for students)valid for 5 months and I am going back home to india but my flight is through london heathrow so do I need the airport transit visa too? I have read that I dont require it (http://www.immihelp.com/visas/nonustransit.html http://www.immihelp.com/visas/nonustransit.html) but your case is exactly mine so can you please help me out here