Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

RICARDO PLC

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

YES

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

NO

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

NO

An event changing the breakdown of voting rights

NO

Other (please specify):

N/A

3. Full name of person(s) subject to the notification obligation:

IMPAX ASSET MANAGEMENT LIMITED

4. Full name of shareholder(s) (if different from 3.):

Impax Environmental Markets plc,

Impax Environmental Markets Trust

AUD, Impax Environmental Markets (Ireland) Fund, LGSS, Parvest Environmental Opportunities Fund, The Environment Agency Fund

5. Date of the transaction and date on which the threshold is crossed or reached:

12 JANUARY 2011

6. Date on which issuer notified:

13 JANUARY 2011

7. Threshold(s) that is/are crossed or reached:

5%

8. Notified details:

A: Voting rights attached to shares

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights

Direct

Direct

Indirect

Direct

Indirect

Ordinary

Shares

2,547,144

5.024%

2,360,644

NIL

2,360,644

NIL

4.592%

GB0007370074

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate

Exercise/ConversionPeriod

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

NIL

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Exerciseprice

Expirationdate

Exercise/Conversionperiod

Number of votingrights instrumentrefers to

% of voting rights

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

2,360,644

4.592%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable:

Impax Environmental Markets PIX (1,048,115 Shares 2.0388%)Impax Environmental Markets Trust AUD (5,100 Shares 0.0099%)

Impax Environmental Markets (Ireland) Fund (516,892 Shares 1.0036%)LGSS Fund (90,010 Shares 0.1751%)

Parvest Environmental Opportunities Fund (549,167 Shares 1.0683%)The Environment Agency Fund (152,360 Shares 0.2964%)

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will cease to hold:

N/A

12. Date on which proxy holder will cease to hold voting rights:

N/A

13. Additional information:

14. Contact name:

Compliance Officer

15. Contact telephone number:

+44(0)20 74341122