Lloyd’s insurer Hiscox has launched a legal battle against the owners of what will be the City’s tallest tower after workers on the site smashed holes and leaked water into the insurer’s adjacent offices.

Hiscox was due in court on Wednesday to seek an interim injunction against Arab Investments, developer of the Pinnacle tower – also known as the Helter Skelter – and demolition contractor Keltbray, over works on the site.

The site adjoins Hiscox’s London headquarters at No 1 Great St Helen’s. Hiscox is seeking to prevent builders exceeding pre-agreed vibration levels while they carry out demolition work on the site.

Hiscox said in a statement: “We have had water ingresses, holes pecked in and innumerable scrapes and bashes to our building. Access to Great St. Helen’s is regularly blocked so that at times it is isolated from the emergency services. We just want those involved in the development to have regard for their neighbour.”

The statement added there had been serious breaches of agreed noise and vibration levels.

Arab Investments confirmed that damage had been done to the Hiscox building, but said it had been rectified and this was not the subject of the court injunction.

A spokesman for Arab Investments said that the legal action focused on disruption caused by the works.

He continued: “Hiscox wants the trigger levels for the vibrations to be absolute, so that any breach of them is a contempt of court. But this is simply impossible on a demolition site. We will be fighting against this.”

Hiscox has also asked the Corporation of London to have contractors to the site, Keltbray and Mace, removed from the Considerate Contractors list.

Hiscox issued legal proceedings on 5 December 2007. The Corporation of London served a notice under Section 60 of the Control of Pollution Act on 6 December 2007 in respect of the site.

Keltbray declined to comment.