The Law Society is threatening to revoke Michael Dalton's licence if he does not make a "goodwill payment" to the society.
Dalton, the Portsmouth solicitor who is seeking a judicial review of his SIF bill, says the Law Society is demanding that he and four of his staff pay their contribution, or risk being barred from practising.
He accuses the society of back-tracking on an agreement not to revoke his practising certificate because he refuses to pay his Solicitors' Indemnity Fund contribution.
However, Dalton claims that the Law Society said he would not have to make a contribution to SIF during the judicial review process.
He says that hours before he applied for judicial review last October, he was given the assurance by the society's legal and constitutional adviser, Anne Coles.
Dalton is furious that the Law Society is now insisting he has to pay his basic SIF contribution (though not the claims loading) in what Chancery Lane calls a "goodwill payment".
However, Coles says that the undertaking not to revoke Dalton's practising certificate had been given informally.
"I never thought that Dalton was not going to pay his contribution. He said that he had financial hardship and we had offered him options on payment," she says, "as a form of goodwill he should make a payment."
The row will be resolved by a judge before Dalton, represented by Cherie Booth QC, seeks judicial review of his SIF payments on 24 March.