A group of pension funds is suing asset manager Henderson Global Investors over claims that it took too much risk with one of its infrastructure funds.

The group, which is made up of around 30 pension funds and other institutions, including those at Bupa, the BBC and Tesco, has filed papers in the High Court after seeking legal action for over a year.

The claim relates to the Henderson PFI Secondary Fund II, which lost two-thirds of its value between 2006 and 2009 after acquiring construction firm John Laing.

The group claim that the fund was meant to be a low risk, inflation-proof fund, and that it took on too much risk in acquiring John Laing, breaching its terms of agreement with shareholders.

The proceedings represent the first time in the UK that a group of institutional investors has sued an asset manager and media reports suggest the size of the claim could be as high as £450 million.

Henderson issued a statement this morning acknowledging that complaints had been made more than a year ago and that a ‘majority’ of Fund II’s investors are suing.

It said, ‘The proceedings involve alleged breach of mandate and misrepresentation. All the claimants are sophisticated investors. We have considered these complaints carefully.

‘We are confident we have no legal liability to investors in this fund. We will vigorously defend these proceedings.’