President Vladimir Putin keeps making strategic errors in his war in Ukraine because nobody around him can call out his mistakes, according to the head of the UK's GCHQ spy agency.Putin's decision-making is "flawed" because he has "little effective internal challenge," according to text of a speech from Jeremy Fleming, previewed by Insider ahead of its delivery on Tuesday.Over the past six weeks, Ukraine has retaken hundreds of square miles of territory, including in areas that Russia claimed to have annexed and considers its own land.Fleming's speech was due a day after Putin launched missiles and drone swarms towards Kyiv and several other Ukrainian cities and regions, well beyond the front lines of Ukraine's ground war.Putin framed this as retaliation for an attack on the Kerch Strait Bridge over the weekend, state media reported."