Party sources think they have so far won in 47 seats including Wimbledon, North Cornwall and Henley.
The party’s predicted strong performance in the election follows its unorthodox approach to campaigning which saw leader Sir Ed take on a number of eye-catching stunts, including going down a waterslide and bungee-jumping.
The party decided to focus resources on a limited number of seats, largely targeting Conservative-held areas in the south of England.
Responding to the exit poll, published at 22:00 BST, Sir Ed said his party was “on course for our best results in a century”.
“I am humbled by the millions of people who backed the Liberal Democrats to both kick the Conservatives out of power and deliver the change our country needs.
“Every Liberal Democrat MP will be a strong local champion for their community standing up for the NHS and care. Whether you voted for us or not, we will work day in and day out and we will not let you down.”
In his own seat of Kingston and Surbiton, Sir Ed increased his majority from 11,000 to 17,000.
In his acceptance speech, he said his party had listened to voter concerns, adding: “We hear you loud and clear.”
If the exit poll is accurate, the Liberal Democrats could return to Parliament as the third largest party, overtaking the SNP.
They have not held that position since 2015, when they were punished by voters for going into coalition government with David Cameron’s Conservatives.
