I saw this headline from the Washington Post online, and I thought there was a grammatical error. Then I realized it was just English, with it's constant confusion over meaning and different parts of speech that different words can have. I wondered if there were a leader called "May" who wants elections. Was the comma put there by mistake, so the Britains may want (call for) an election? In that case the "s" at the end of "calls" would be an error. Maybe it meant that there would be a call for elections in May. After several readings, I finally figured it out.

When headlines are in all caps and devoid of punctuation, getting the meaning can be a challenge.