Interserve is to close its defined benefit pension scheme to future accrual for around 900 employees despite posting a 18.7% increase in interim pre-tax profits.

The support services and building company, which employs around 26,900 staff in the UK, will implement the changes for affected members by the end of the year as part of efforts to manage the scheme's deficit, which is expected to be around £250 million.

In its half-year results for 2009 Interserve said that a full strategy review had been completed, and initial conclusions implemented in conjunction with the scheme’s trustees. These measures are designed to reduce investment risk through greater asset diversification and matching of inflation and interest volatility with scheme liabilities.