The High Court has struck out a claim after refusing permission to a claimant to make major changes to her case.

Singapore private investor Quah Su-Ling had applied to the commercial court to amend her particulars of claims three weeks before her trial was due to start on 4 March.

Quah, chief executive of IPCO International Ltd, was in dispute with the bank Goldman Sachs over a private wealth-management account to increase her shareholding in another company.

She claimed Goldman Sachs was in possession of critical information about the company which showed the market value was too high.

She issued proceedings in the Queen’s Bench Division in November 2013, with particulars of claim served 15 days later.

The High Court heard that proceedings were commenced without Quah obtaining any expert advice but based on her ‘own experience and opinions’. But by March, she was aware that expert advice was ‘crucial’ to her case.

The trial was set for February 2015 and was allowed to be delayed until this month to avoid any overlap with arbitration proceedings in which Quah was involved in Singapore.

But with just weeks until trial, Quah’s legal team, from London firm Devonshires Solicitors, wrote to Goldman Sachs’ representatives to say it was preparing an application for permission to amend, which would ‘abandon large parts’ of the case.

She argued her current claim was ‘unsustainable’, which only became clear with expert guidance in January 2015.

Accepting her application was made late, she argued the new case arises from disclosure and witnesses statements served on behalf of the bank, she was under strain from other proceedings and lacked funding.

Mrs Justice Carr said she was ‘troubled’ by deficiencies in the explanations given by Quah, particularly the lack of any reason for her not instructing an expert at the outset.

She said that in the light of the scope and nature of the proposed amendments, the weakness of the new case, the poor quality of the explanations for the delay in advancing it and the prejudice resulting to GS, she was not persuaded that an amendment was a ‘just and proportionate outcome’, nor consistent with the overriding objective.

The judge admitted that the decision may be seen as ‘harsh’ given the consequences for Quah’s case but she added: ‘This is modern-day commercial litigation.

‘Very late applications for permission to amend in circumstances where a) there is no good reason for the delay and b) amendment would result in real disruption or prejudice to the parties and/or the court are unlikely to be allowed, irrespective of the merits of the proposed amendment.’