Linklaters is gearing up to fight a £3.5m court battle in the autumn against five defendants over issues relating to the maintenance of its City HQ.

Following a recent ruling (21 May), the magic circle law firm's original claim against construction and civil engineering company Sir Robert McAlpine and its holding company will now include a total of three additional parties.

Linklaters initially filed a claim in October 2009 relating to defects discovered in 2006 in the pipework in Silk Street. The firm claimed the cost of replacing the pipes from McAlpine, which was brought in as the main contractor to refurbish the building in 1996.

At the end of last year, McAlpine brought How Engineering Services and How Group (HOW) into the proceedings as third and fourth defendants, claiming that as subcontractors, liability also falls with them. In addition HOW brought Southern Insulation into the proceedings as a fifth party after subcontracting work to them.

Southern asked to be removed from the proceedings. However, Mr Justice Akenhead ruled against Southern's application last month (21 May). Unless Southern successfully appeals Akenhead's judgment they will also be included as a defendant in the autumn trial.

Linklaters has also launched a £3.5m claim against HOW in relation to the same issue, which will be heard at the same trial.

Linklaters is representing itself, with Atkin Chambers' Stephen Dennison QC instructed as counsel, while McAlpine has turned to Glovers Solicitors partner Philip Eyre, with Atkin Chambers' Peter Fraser QC instructed as counsel.

HOW is being represented by Kennedys, with Four New Square's David Turner QC instructed as counsel, while Southern has turned to Clyde & Co partner Victor Rae-Reeves, with 39 Essex Street's Richard Wilmot Smith QC instructed as counsel.