The FT lists it as one of Theresa May’s five big mistakes:
"Mrs May’s decision in April 2017 to call a snap general election will be remembered as an unenforced error of epic proportions.
At the time, the Tories enjoyed a huge lead in the opinion polls. Senior colleagues including David Davis, the then Brexit secretary, urged her to go to the country to increase Tory representation in the House of Commons, bolster her political capital and gain more room for manoeuvre to push though an exit deal.
When the count came in on June 9 Mrs May had lost her slender Commons majority and her political authority was shattered.
But perhaps a still bigger blunder than calling the poll was the election campaign itself. Mrs May had already been dubbed the “Maybot” by one newspaper sketchwriter. Now, her robotic style was on prime time for weeks.
Urged by her joint chief of staff, Nick Timothy, Mrs May produced a manifesto that included a policy that would force the elderly to pay all but the last £100,000 of their care costs. This was almost immediately dubbed a “dementia tax”.
“They put out policies that hadn’t been road tested,” said Paul Goodman, editor of the ConservativeHome website. “The election was not the mistake, it was not being clear what it was for.”"
www.ft.com/content/2ea1b40c-7d7f-11e9-81d2-f785092ab560?syn-25a6b1a6=1