Trading Statement

Costain Group PLC
01 July 2005

Costain Group PLC
('Costain' or 'the Group')

Trading Update

Ahead of the announcement, on Wednesday 31 August 2005, of interim results for
the six months ended 30 June 2005, Costain is issuing a brief trading update.

Since the Annual General Meeting, when the Group confirmed that it had made a
strong start to 2005, the forward order book has been further boosted by the
award of a significant oil and gas contract in Iran and the securing of major
AMP4 contracts with United Utilities, Southern Water and Bristol Water.   The
forward order book currently stands at a record £1.6 billion.

In addition, preferred bidder status has also been achieved on over £700 million
of major roads schemes and a £100 million framework agreement in the nuclear
sector.

Due to the usual delay during a General Election period in releasing central
Government funds for major highway infrastructure projects, and the extended
nature of negotiations during the transition phase from AMP3 to AMP4, the
results for the first half, which will be prepared in accordance with
International Financial Reporting Standards ('IFRS'), will not reflect the full
extent of the new contract awards.  With these revenues being deferred into the
second half, the outlook for the year remains in-line with the Board's
expectations.

For comparative purposes, the Group will publish, on 17 August, a restatement of
its 2004 interim and full-year accounts under IFRS and it will hold a conference
call for analysts and investors that morning at 08:00.

Stuart Doughty, Chief Executive, comments:

'I am delighted with the substantial contract wins during the first half.  This
undoubtedly reflects the progress we have made over the last few years in
rebuilding the Costain brand and establishing a reputation for excellence.  The
transition to partnering with our clients and focusing on long-term framework
agreements has given the Group an outstanding visibility and quality of earnings
which we will report on in greater detail in August.'

                                                                     1 July 2005

Enquiries:

Costain Group PLC                            Tel: [phone]
Stuart Doughty, Chief Executive
Charles McCole, Finance Director

College Hill                                 Tel. [phone]
Mark Garraway
Matthew Gregorowski


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