Costain Group PLC
("Costain" or "the Company")

Transactions in shares by Persons Discharging Managerial Responsibilities ("PDMRs")

This notification is made in accordance with DTR 3.1.4(1).

(a)  Total Beneficial Holding of Shares

Costain Group PLC announces that, following the exercise of share awards granted under the Company's Long Term Incentive Plan as detailed in section (b) below, the following Directors hold the number of ordinary shares of 50 pence each in the share capital of the Company (the 'shares') as set out in the table below:

(b)   Long Term Incentive Plan

On 09 May 2012, awards were granted under the Costain Group PLC Long Term Incentive Plan (the "Plan") to certain directors. The awards were granted in the form of nil cost options.

The awards became exercisable on 09 May 2015 for a period of up to ten years from the date of grant.

On 11 May 2015 the following directors exercised their options to acquire the number of ordinary shares of 50 pence each in the capital of the Company as set out in the table below.  As noted below, these individuals sold a proportion of the resulting ordinary shares, including sufficient to satisfy their income tax and national insurance liability arising on exercise, and retained the remaining shares.

* as adjusted following the Capital Raising in March 2014

The Company was informed of the above transactions on 11 May 2015.

 12 May 2015

 Enquiries:

Costain Group PLC                                                                                            Tel: 01628 842444
Tracey Wood

Company Secretary