The secret Tory past of a Labour MSP has been uncovered following an investigation by the Sunday Herald.

Margaret McCulloch sneaked a seat at Holyrood as third placed Scottish Labour candidate on the Central Scotland list in 2011 - and today she will ask party members to select her as candidate for next year’s Holyrood elections.

But we can reveal McCulloch stood for the Tories in the same region in 2003 only to lose out to Margaret Mitchell MSP, the Scottish Conservatives Party’s justice spokeswoman.

McCulloch appeared alongside Mitchell on an official Tory election leaflet which we obtained from library archives.

The former businesswoman from East Kilbride, who was shadow minister for town centres when Jim Murphy was Scottish Labour leader, also stood for the Tories in Cumbernauld and Kilsyth.

During the campaign she gave an interview to a newspaper as she canvassed voters in which she admitted she “used to vote Labour because my parents always voted Labour”.

McCulloch also bemoaned hostility to Tories in Lanarkshire, described doors being slammed in her face and spoke of her hope that she could hold on to her deposit. She didn’t.

McCulloch could only persuade 978 people to support her and came in fifth behind Labour’s Cathie Craigie and the SNP, Scottish Socialist and Liberal Democrat candidates.

McCulloch also stood against former Labour MP and defence minister Adam Ingram in East Kilbride in 2001 but only polled 4,000 votes to Ingram’s 22,000.

In the 2003 newspaper interview, which is in an archive unavailable online, McCulloch said: “I stood for the council in East Kilbride four years ago and the mood was hostile. Almost everyone would say 'No chance, I'm not voting for you' and slam the door.

“I stood again at the General Election two years ago and the feelings weren't as strong. Now I'm finding you can talk to people. People are more open-minded. They've had six years of Labour Government so they can make comparisons.”

But by 2007 McCulloch had abandoned her ambition to become a Tory politician and instead tried and failed to be elected to South Lanarkshire Council as Scottish Labour candidate for East Kilbride West.

In 2011 she managed to win enough votes from party members to scrape a third place finish in Scottish Labour’s Central Scotland regional list selection but no one expected her to become an MSP.

However, the SNP landslide saw Labour lose five constituencies in the region and the electoral system meant McCulloch had a seat at Holyrood.

There is now little evidence online of the MSP’s Tory past. Typing ‘Margaret McCulloch Conservative candidate’ into Google throws up a Wikipedia page stating that she stood for the party - but when it was opened last week all trace of this information appeared to have been removed.

After the Sunday Herald got in touch it appeared to have been amended again to show her Conservative candidacy.

McCulloch has recently sought to consolidate her position in Scottish Labour by seeking selection to stand for the Scottish Parliament in East Kilbride, but she was trounced by council worker LizAnne Handibode, who won by 178 votes to McCulloch’s 87.

When Jackie Burns stood down as Scottish Labour candidate for Hamilton, Larkhall and Stonehouse citing personal reasons, McCulloch sensed another opportunity and she threw her hat in the ring.

A selection meeting today at 12.30pm will ask party members to choose between McCulloch, trade union activist Hugh Gaffney, local councillor Monica Lennon or Jim Lee, a development manager at the Scottish Fair Trade Forum.

But Scottish Labour sources have indicated that they would rather see anyone but McCulloch selected.

“The fact that she was a Tory went largely unnoticed in 2011 because the list selections were treated as a paper exercise,” said one source, who asked not to be named. “But she’s toxic for the party, which is desperately trying to kill off this so-called ‘Red Tory’ image.”

Another senior party source, who also asked to remain anonymous, added: “We simply cannot afford to have a carpet bagger with a true blue Tory past if we are to have any chance of winning back the seat from the SNP. There are a lot of members who are appalled at the prospect.

“Margaret is not a bad person but she was heavily defeated in the East Kilbride selection for good reason.”

A spokesman for the Scottish Conservatives said “it is a matter for the Labour Party” but a Scottish Labour spokesman declined to comment.

McCulloch said: "I don't think it is appropriate to comment on an ongoing selection process.

"What I can say is that if I learned anything from my short time with the Conservatives it's that I'm not one of them. I believe too much in the rights of working people.

"I am proud to represent Scottish Labour and to have campaigned and worked for the party for almost twelve years. I have proven my commitment to the Labour Party and the better society it stands for."