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 Deferred Share Bonus 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)  Deferred Share Bonus Plan

On 03 April 2013, awards were granted under the Costain Group PLC Deferred Share Bonus Plan ("the Plan") to certain Directors of the Company.  The awards were granted under the Plan in the form of options with a nil exercise price over a fixed number of shares (the "Deferred Award") and options over a fixed value of shares (the "Combined Deferred Award") granted in combination with an HMRC approved market value option over a fixed number of shares (the "Option"), (together "the Awards").  No consideration was paid for the grant of the Awards.

The Awards became exercisable on 03 April 2015 for a period up until the tenth anniversary of grant.

On 03 April 2015 the following Directors exercised their options to acquire the number of ordinary shares of 50 pence each in the share capital of the Company as set out in the table below.  As detailed below, these individuals sold a proportion of the resulting ordinary shares, including sufficient to satisfy the exercise price of £2.59 (in respect of the Option only) and their income tax and national insurance liability arising on the exercise, and retained the remaining shares. In addition, in accordance with the Rules of the Plan, dividend shares were awarded representing the value of dividends that would have been due on the vested Deferred Award shares during the period between 03 October 2013 and 03 April 2015.

* as adjusted following the Capital Raising in March 2014

The Company was informed of the above exercise of options on 03 April 2015 and the number of shares sold/retained following exercise on 08 April 2015.

08 April 2015

Enquiries:

Costain Group PLC                                                                                        Tel: 01628 842444
Tracey Wood

Company Secretary