Costain Group Regulatory News (COST)

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

Deferred Share Bonus Plan

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

On 12 April 2011, awards were granted under the Costain Group PLC Deferred Share Bonus Plan ("the Plan") to certain directors. 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 Awards"). No consideration was paid for the grant of the Deferred Awards.

The Deferred Awards became exercisable on 12 April 2013 for a period of up to ten years from the date of grant.

The Company announces that on 12 April 2013 the following director exercised his option to acquire the number of ordinary shares of 50 pence each in the capital of the Company set out in the table below. As noted below, this individual sold a proportion of the resulting ordinary shares to satisfy their income tax and national insurance liability arising on the exercise and retained the remainder. 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 13 October 2011 and 12 April 2013.

The Company was informed of the above transactions on 12 April 2013.

15 April 2013

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