The chief executive of Boston Scientific promised to keep buying heart devices from an Israeli supplier even while his company was copying the devices in a top secret plant in Dublin, a New York court heard yesterday.

Dr Kobi Richter, the joint owner of the supply company, Medinol, was giving evidence in a $1.5 billion (€1.24 billion) lawsuit against Boston Scientific for breach of contract.

The Manhattan court has already found in favour of Medinol and is now to decide how much damages the company is to receive from Boston Scientific.

In his evidence, Dr Richter told the Federal District Court in lower Manhattan that Boston Scientific's chief executive Jim Tobin consistently made promises that Boston Scientific would continue to use Medinol's heart stents - medical devices used to keep heart values open during surgery.

Dr Richter said that Mr Tobin's assurances continued well into 2000, a time when Boston Scientific was manufacturing Medinol's stents at a secret plant in Sandyford in Dublin.

However, Boston Scientific said that it was forced into the situation because of Medinol's unreliable supply of stents.

The agreement between the two companies fell apart in early 2002 and they have been locked in litigation since that time.

Judge Alvin Hellerstein has said that he wants the companies to settle the case but they have failed to reach an agreement on how much Boston Scientific should pay.

Boston Scientific says the claim is not worth more than $300 million. The medical devices company is countersuing for $400 million for breach of contract.

More than 80 boxes of legal papers lined the courtroom wall yesterday, many of them displaying the names of officials at Boston Scientific's Galway plant, who made depositions in the case at Medinol's insistence.