The last of the six fingerprint specialists at the heart of the Shirley McKie scandal has been sacked, prompting another legal action which could lead to a compensation bill of hundreds of thousands for Scottish ministers.

Fiona McBride, who has worked for the fingerprint service for more than 22 years, was told to leave on Tuesday after refusing to accept a move to a different post for less than half her salary.

Ms McBride, 42, has taken legal advice and believes she has a strong case for compensation on the grounds of unfair dismissal.

Last month four of her colleagues accepted a confidential redundancy package which included a gagging order prohibiting them from speaking about their ordeal.

Ms McBride, who has spent years working on behalf of Scottish ministers, said she is delighted she can now speak out for the first time in the 10-year debacle.

The experts identified former policewoman Shirley McKie's thumbprint at the scene of a murder in 1997. Ms McKie was cleared of perjury in 1999 after the jury accepted her claim that the fingerprint was not hers.

Last February Scottish ministers agreed to pay her a £750,000 out-of-court settlement in the hope of putting a line under the case.

However, a parliamentary inquiry into the affair last year failed to resolve the dispute and the experts stood by their identification. Last month Robert McKenzie, Allan Dunbar, Hugh McPherson and Charlie Stewart took redundancy packages estimated at between £70,000 and £100,000 after being told they would lose their jobs on April 1 once the new Scottish Police Services Authority (SPSA) took over the fingerprint service. Ms McBride's remaining colleague, Tony McKenna, agreed to be redeployed to Strathclyde Police.

Ms McBride was last week offered a move to work at Crimestoppers for £13,000 a year, compared with her more than £30,000 a year salary as a fingerprint expert.

"My colleagues were threatened and frightened out of their jobs even though they had no reason nor right to get rid of us," she said. "We had been exonerated by the Justice 1 Committee report and have been working since the McKie case, yet they decided to get rid of us now for political reasons."

Last year David Mulhern, the acting head of SPSA who has since been given the top job, said the six experts would have to accept redeployment or leave after ministers agreed to pay Ms McKie compensation.

Iain McKie, Shirley's father, said the removal of the experts was a "necessary cull" in order to reinstate the integrity of the service. However, others, including Ken Macintosh, former Labour MSP for Eastwood in Renfrewshire, said it was "shameful" the experts had been forced out.

David Mulhern, chief executive of the Scottish Police Services Authority, said: "As a matter of policy, the Scottish Police Services Authority will not discuss staff matters.

"We have no further comment on this matter."