The High Court battle between Multiplex and Cleveland Bridge over Wembley Stadium took a new twist this week when it emerged that Tony Caletka, a high-profile expert witness, has been appointed by Cleveland Bridge.

The news comes after the Civil Justice Council drafted a code of practice for expert witnesses. Under the code, which comes into force in September, experts and the parties that employ them could be forced to pay punative court costs if they fail to act objectively.

Caletka, who has been instructed to be Cleveland Bridge’s planning expert, is one of several high-profile expert witnesses to have had their evidence criticised – some say unfairly – by the court.

Caletka hit the headlines in April this year when Judge Wilcox singled him out for his evidence in support of John Laing’s case against Great Eastern Hotel.

Martin Scott, a partner at law firm Walker Morris, which is representing Cleveland Bridge, said Caletka was one of four expert witnesses it has working on the case. The other three are experts in engineering, quantity surveying and efficiency.

It is thought that Multiplex has also appointed experts ahead of the High Court trial expected next April.

Caletka is one of several expert witnesses to have had their evidence criticised – some say unfairly – by the court

In the period before the trial, the experts are expected to draw up reports in support of each of the parties’ claims. The main issues the experts are likely to deal with will be claims of defects, delays and breach of contract. Later they may be required to give evidence in court.

The code of practice, unveiled last month by Lord Phillips, master of the rolls, is the latest attempt to rid experts of the reputation of being “guns for hire”.

The code, which has been agreed by the Academy of Experts and the Expert Witness Institute, says courts may make cost orders against “expert witnesses who by their evidence cause a significant expense to be incurred and do so in flagrant and reckless disregard of their duties”.