Trading Update

Costain Group PLC
03 July 2003



                                COSTAIN GROUP PLC

                                 Trading Update

Costain is providing the following trading update ahead of its interim results
for the six months to 30 June 2003, which will be announced on 3rd September
2003.

At the time of the preliminary results in March, the Chairman confirmed that the
Group was ahead of plan in meeting its objectives of i). turnover growth of 15%
per annum and ii). a continuous improvement in profitability to a 3% operating
margin for Group operations over the five years of the strategic plan unveiled
in November 2001.  This continues to be the case.

Underpinned by the Government's commitment to healthcare and transport
expenditure programmes, the UK infrastructure market remained buoyant throughout
the first half.

As at the end of first half, trading overall has continued in line with
expectations and the Board is confident of reporting further progress.

3 July 2003

ENQUIRIES:

Costain Group PLC                                    Tel: [phone]
Stuart Doughty, Chief Executive
Graham Read, Public Relations

College Hill                                         Tel: [phone]
Mark Garraway
Matthew Gregorowski

Arbuthnot Securities
Nick Donaldson                                       Tel: [phone]
                                                     Mob: [phone]


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