Holdings in Company

For filings with the FCA include the annex

For filings with issuer exclude the annex

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Horizon Discovery Group plc

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

An acquisition or disposal of voting rights

√

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

√

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

An event changing the breakdown of voting rights

Other (please specify):

3. Full name of person(s) subject to thenotification obligation: iii

Aviva plc & its subsidiaries

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

Registered Holder:

Available Upon Request13,467*

BNY Norwich Union Nominees Limited120,092*

Chase (GA Group) Nominees Limited3,797,395*

State Street Nominees Limited748,144*

* denotes direct interest

Chase (GA Group) Nominees Limited793,958

Chase Nominees Limited161,503

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

5 July 2016

6. Date on which issuer notified:

6 July 2016

7. Threshold(s) that is/are crossed orreached: vi, vii

5% to 4% Change at Direct Interest Level (Box 8A)

8. Notified details:

A: Voting rights attached to shares viii, ix

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 x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary SharesGB00BK8FL363

6,337,292

6,337,292

5,634,559

4,679,098

955,461

4.97%

1.01%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

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

% of votingrights

RIGHT TO RECALL LOANED SHARES

N/A

N/A

307,792*

*Direct interest

0.33%

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

5,942,351

6.31%

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

The voting rights are managed and controlled by Aviva Investors Global Services Limited & Friends Provident International Limited, with the following chains of controlled undertakings:-

Aviva Investors Global Services Limited:

· Aviva plc (Parent Company)

· Aviva Group Holdings Limited (wholly owned subsidiary of Aviva plc)

· Aviva Investors Holdings Limited (wholly owned subsidiary of Aviva Group Holdings Limited)

· Aviva Investors Global Services Limited (wholly owned subsidiary of Aviva Investors Holdings Limited)

Friends Provident International Limited:

· Aviva plc (Parent Company)

· Aviva Group Holdings Limited (wholly owned subsidiary of Aviva plc)

· Aviva Life Holdings UK Limited (wholly owned subsidiary of Aviva Group Holdings Limited)

· Friends Life FPG Limited (wholly owned subsidiary of Aviva Life Holdings UK Limited)

· Friends Life FPL Limited (wholly owned subsidiary of Friends Life FPG Limited)

· Friends Life Limited (wholly owned subsidiary of Friends Life FPL Limited)

· Friends Life and Pensions Limited (wholly owned subsidiary of Friends Life Limited)

· Friends Provident International Limited (wholly owned subsidiary of Friends Life and Pensions Limited)

Proxy Voting:

10. Name of the proxy holder:

See Section 4

11. Number of voting rights proxy holder will ceaseto hold:

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

13. Additional information:

Figures are based on a total number of voting rights of 94,176,283 as per the Company's Additional Listing Announcement of 29 June 2016.

14. Contact name:

Neil Whittaker, Aviva plc

15. Contact telephone number:

01603 684420