Friday’s vote will have an immediate impact as it slims down PM Boris Johnson's parliamentary majority to one.
Voting took place in the Welsh sheep farming community of Brecon and Radnorshire, where Conservative MP Chris Davies was forced to step down after being criminally convicted of expenses fraud.
Johnson had stopped by on Tuesday to help out Davies who is also a staunch supporter of Brexit.
Davies protested his innocence and contested the seat again, but Liberal Democrat’s Jane Dodds overturned his previous majority by a margin of 1,425 votes.
Following her win, she added that her very first act as MP upon arrival in Westminster will be “to find Boris Johnson wherever he is hiding and tell him loud and clear: stop playing with the futures of our communities and rule out no-deal Brexit".
Since the 1990s, control of Brecon and Radnorshire has swayed between the Conservatives and the Liberal Democrats.
During the Brexit referendum, 52 percent voted to leave the EU.
But the return of this Welsh constituency to Liberal Democrats comes at a major expense to the party.
Dodds was able to benefit from a so-called “remain alliance” that saw two smaller pro-EU parties back her bid.
Her win, albeit small, means Johnson is in danger of being able to control parliament when it resumes from summer break on September 3.
Return to negotiations
The new PM and his government are trying to push for Brussels to return to the negotiating table by insisting that Britain is indeed ready to leave the European Union by the latest deadline October 31.
Added to that is British Finance minister Sajid Javid announcing on Wednesday that an extra 2.3 billion euros is available in funding to prepare for that moment.
But as has been the case in previous actions and discussions relating to Brexit, there are opposing opinions.
Bank of England governor Mark Carney warned on Friday that a no-deal Brexit would be a shock to the country’s economy.
Such a jolt would cause supply disruptions and possibly undermine entire sectors such as agriculture and cars cautioned Carney.
An official document obtained by the British broadcaster Sky News warned of potential “consumer panic” and gaps in security in the weeks to come.
And MPs are already plotting ways to ensure he doesn’t follow through on his promise to take Britain out of the EU by its October deadline, for fear of the economic repercussions.
In short, that leaves the new PM dependent on just a few legislators at one of the most crucial moments in British history since World War II.