Assets worth millions of pounds said to be controlled by Dame Shirley Porter have been frozen under court orders secured by Westminster Council.
The scandal ended Dame Shirley's political career
Dame Shirley, the council's former leader, owes Westminster £37m in surcharges following the "homes for votes" scandal in the 1980s.
The council says it has made a significant breakthrough in its attempt to recover the shortfall owed to local taxpayers.
It says assets - understood to be worth about £30m - have been frozen in Guernsey, but Dame Shirley says she has no connection with the money.
She said the council's investigators had sought to involve off-shore trusts whose principal beneficiaries had no connection to the case.
The council has argued the trusts are a sham designed to disguise her control over the family fortune and therefore is money owed to the council for her financial misconduct.
The council also says a further order has been granted to freeze Dame Shirley's assets alleged to be held by her son John Porter.
It says this is a step forward but that getting hold of the money will depend upon successful enforcement action.
In the 1990s, the district auditor found Dame Shirley guilty of squandering millions of pounds by unlawfully selling off council flats on the cheap, simply to boost the number of Tory voters.
She was cleared by the Court of Appeal in 1998, but in 2001, the House of Lords ruled she did have to pay back the money she claimed she did not have.
The Tesco heiress, who now lives in Israel, was once said to be the 20th richest woman in Europe with an estimated
fortune of £60m, but last year when she was ordered by a court to disclose her assets, she listed just £300,000 worth.
Westminster, which has spent about £1m pursuing the heiress, said it had decided to ask various courts to lift gagging orders which had previously prevented details of its legal actions being publicised.
Colin Wilson, head of legal services at Westminster Council, said the council had been engaged in some "very intense activity" over recent months.
"We have now made substantial progress. In fact we have obtained disclosure orders against 14 different companies and individuals in the UK, in Guernsey and in the British Virgin Isles, " he told BBC London.
These orders require respondents to disclose information to the council about Dame Shirley's past and present wealth.
"We have gained a substantial amount of information from those disclosures and in addition, we have frozen in bank accounts many millions of pounds."