title: How to convert list of historical local timestamps to UTC in q kdb?
body: <p>I have a list of historical timestamps specified in London local time (GMT/BST). How can I transform these into UTC timestamps?</p>
  
  <pre><code>local_times:(2019.04.17T20:00:00.000;2019.01.17T20:00:00.000);
  expected_utc_times:(2019.04.17T19:00:00.000;2019.01.17T20:00:00.000);
  </code></pre>