Lloyd's chief executive Nick Prettejohn has travelled to Washington DC to attack a bill that could wreck Lloyd's attempts to recover up to £60m from 250 US Names.

Prettejohn told the US media that the bankruptcy reform bill would enable US Names who have refused to settle their debts, to avoid the Jaffray judgment.

In the Jaffray case, Mr Justice Cresswell threw out allegations that Lloyd's had covered up from Names the market's £8bn spiral of asbestos claims in the 1970s and 1980s. He ordered the losing 700 Names to pay up.

Prettejohn said: “We have been through an extensive legal process in the UK and the US to establish our right to collect these debts, yet now a clause has been inserted into the bill that overturns the whole thing.”

The insurance market has also hired defeated Republican presidential candidate Robert Dole to unleash a fierce lobbying campaign against the bill.

Dole, who retired as a senator after his unsuccessful presidential bid in 1996, is now a key Washington DC lobbyist. He is reported to charge a daily fee of around £33,000.

A spokeswoman for Lloyd's said that if the bill became law it would be difficult to recover its debts in the US.

Lloyd's faces an uphill task since the bill has been passed by the US House of Representatives by a two to one margin.

If passed by the US Senate, the bill would prevent non-US courts from enforcing judgments for debt against US citizens.

However, it carries the proviso that investors demonstrate they were victims of misrepresentation or fraud between 1975 and 1994.

These years encapsulate the period when Lloyd's incurred heavy losses from asbestos claims.

In January Lloyd's wrote to 700 Names worldwide, offering to write-off two-thirds of the £300m they owed from the Jaffray case.

In return, Lloyd's said the Names would have to renounce their right to pursue further legal action.