Amanda Bland has quit Reform UK Scotland to sit as an independent MSP.
Her resignation leaves Reform as the third-largest group in the Scottish Parliament, one member behind Labour.
Bland, a list MSP for Central Scotland and Lothians West, has yet to comment publicly.
Reform UK has called on Bland to step down as an MSP.
A Reform spokesperson said: “We can confirm Amanda Bland has resigned as a Reform UK member of the Scottish Parliament to sit as an independent MSP.
“We are proud of a talented and united team of MSPs at Holyrood who have supported each other at every step of the way.
“Amanda Bland should reflect on her reasons for choosing to isolate herself from that team of capable individuals.
“It is incumbent on her to resign as a regional MSP for Central Scotland and Lothians West and allow her constituents to be represented by the next Reform candidate on that list.”
Under the additional member system (AMS) active in Scotland, voters are issued two separate ballot papers: one to elect constituency MSPs via first past the post, and a second “regional” ballot to elect 56 additional MSPs. Before the election, each political party publishes a list of candidates for each region.
If a regional list MSP resigns, no by-election is held. The vacant seat is automatically offered to the next available and willing person on the regional list submitted by that party – in this case Reform UK – at the last election.
Bland was one of 17 Reform MSPs elected to Holyrood in May 2026 as the party broke through in Scotland.
In the May 2026 Holyrood elections, Reform finished joint second with Labour. The Scottish National Party (SNP), led by John Swinney, emerged victorious with 58 seats.
Scottish Labour deputy leader Dame Jackie Baillie said: “No one will be surprised to see chaos at the heart of Reform.
“They have always been a group of chancers, grifters and Tories in disguise.
“Despite all the big talk and promises ahead of the election, Nigel Farage’s party has been utterly useless at holding the SNP to account or getting results for the Scottish people, it’s been a series of stunts, gimmicks, photo calls and precious little else.
“Scottish Labour is now the second largest party at Holyrood, and we will work to hold the SNP to account and deliver better outcomes for the people of Scotland.”