The Liberal Democrats have won the St Albans seat from the Tories, while former justice secretary David Gauke lost his seat in Hertfordshire.
Daisy Cooper has become the first Lib Dem MP for St Albans, replacing Anne Main in one of only three gains made by the party.
The seat had been held by the Conservatives since 2005.
Mr Gauke came second in South West Hertfordshire, but lost out to the Tories’ Gagan Mohindra by 14,408 votes.
He had the Tory whip removed after he voted against Boris Johnson’s Brexit deal and decided to stand as an Independent candidate one month before polling day.
The 48-year old former solicitor said: “I’m obviously disappointed.
“I’ve thoroughly enjoyed being MP for South West Hertfordshire for the last 14 and a half years. It has been a huge privilege.”
In St Albans Lib Dem Ms Cooper received 28,867 votes, 6,293 more than Conservative Mrs Main.