Rebels in Ukraine have released four more international observers in the eastern city of Donetsk, according to reports.
The observers from the Organisation for the Security and Cooperation in Europe (OSCE) were captured by pro-Russian separatists over a month ago.
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The figure is up from £42.3 million in 2014/15 and £56.9 million 2015/16, according to the research.
A study by Which? looked at the work done by councils across the country.
Harry first visited the African country in 2004 on a gap year.