UBS won a court order yesterday barring a group of former and departing executives from poaching clients of its UK wealth management unit.

The Swiss bank accused Vestra Wealth, a new wealth manager backed by Goldman Sachs, David Scott, Vestra's founder, and four departing fund managers of orchestrating a “smash and grab raid” on its British business. Seventy-five UBS employees have joined Vestra since May.

UBS, which has announced €37 billion (£18.6 billion) in sub prime-related writedowns, won the first round of its legal battle yesterday after Mr Justice Openshaw, sitting in the High Court, ruled that there was enough evidence of unlawful conduct to impose a temporary restraining order on Vestra.

UBS said that its business, which has 12,000 clients and £4.6 billion under management, had been left devastated by the mass resignations. Mr Justice Openshaw said that UBS had presented a “formidable” case, suggesting that Mr Scott, aided by senior managers inside UBS, had led a secret campaign lasting several months to woo its staff and clients. Dismissing Vestra's claim that it was competing lawfully, the judge concluded: “It was far more likely in my judgment to be unlawful conspiracy dressed up as lawful competition.”

The judge pointed to transcripts of telephone calls between the departing bankers as evidence of the extent of the plot. In one conversation, Richard Wayne-Wynne, an investment director, said to a client on May 19, shortly after resigning: “All I can say to you is I can assure you that hopefully you'll come with me and you'll get the service you deserve.”

Vestra, which denies conspiracy, said that it was “disappointed” by the ruling and would fight the allegations at trial. Its lawyers submitted into evidence 40 e-mails and letters from departing employees detailing a raft of concerns over the Swiss bank's handling of the wealth management business since it acquired Laing & Cruikshank in 2004. However, Mr Justice Openshaw said that he found the correspondence “quite unconvincing”.

The judge said that Mr Scott was entitled to recruit former colleagues and to attract UBS clients, but he was not entitled to lift an entire client base.

UBS said: “As we have always maintained, this legal action was to ensure that certain senior departing employees abided by the contractual obligations that they agreed to when they joined UBS and to defend UBS's legitimate business interests.”

Vestra said that the injunction had not prevented it from opening for business yesterday with other clients. A full trial is set to be held in early October.

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