Wendy Chamberlain, who is the Chief Whip of the Liberal Democrats and the party’s spokesperson for Scotland and Wales, said that the victory “should send a shiver up the majority of Tory MPs' spines”.
Ms Chamberlain’s comments come after the result of the North Shropshire by-election, which was announced in the early hours of this morning. The Conservatives lost what was an ultra-safe seat to Lib Dem candiadate Helen Morgan by 5,925 votes.
On Good Morning Scotland, Chamberlain said: “We have an electoral system that means that we have safe seats. Owen Patterson's 23,000 majority is more than the votes that I gained when I won my seat in 2019. That’s not actually healthy for democracy”
“If we’re sending a message that none of them are safe and that they need to do better, I think that’s a very important thing.
“It also shows that after 11 years of Conservative Government, there potentially is some light at the end of the tunnel”.
The by-election was triggered by the resignation of Owen Paterson, who was found to have breached lobbying rules for two companies paying him £100,000 a year, while in office as an MP.
Ms Morgan won 17,957 votes, trouncing Tory candidate Neil Shastri-Hurst into second on 12,032.
"Tonight, the people of North Shropshire have spoken on behalf of the British people. They have said loudly and clearly, 'Boris Johnson, the party is over'," Ms Morgan said in her victory speech.
"Your Government, run on lies and bluster, will be held accountable. It will be scrutinised, it will be challenged and it can and will be defeated."
Lib Dem leader Sir Ed Davey, in a statement from isolation after testing positive for Covid-19, said: "This result is a watershed moment in our politics and offers hope to people around the country that a brighter future is possible.
"Millions of people are fed up with Boris Johnson and his failure to provide leadership throughout the pandemic and last night the voters of North Shropshire spoke for all of them.