Exhibit 99.1
UNITED UTILITIES PLC
7 MARCH 2006
We received a notification on 6 March 2006 from Prudential PLC, of its interest as at 2 March 2006, through the registered holders listed below, in 26,707,289 ordinary shares in United Utilities PLC amounting to 3.05 per cent of the issued share capital.
| Registered Holder | Account Designation | Holding | |||||
| MAGIM HSBC GIS NOM(UK) | SALI | 95,887 | |||||
| PRUCLT HSBC GIS NOM(UK) | PAC AC | 25,075,000 | |||||
| PRUCLT HSBC GIS NOM(UK) | PPL AC | 1,129,918 | |||||
| PRUCLT HSBC GIS NOM(UK) | EQBF AC | 45,352 | |||||
| PRUCLT HSBC GIS NOM(UK) | MNBF AC | 75,717 | |||||
| PRUCLT HSBC GIS NOM(UK) | PENE AC | 285,415 | |||||
| Total | 26,707,289 |
Prudential PLC’s subsidiary, The Prudential Assurance Company Limited has also notified its own interest as at 2 March 2006, through the registered holders listed below, in 26,300,805 ordinary shares in United Utilities PLC amounting to 3.01 per cent of the issued share capital and this interest is included in the disclosure given above by Prudential PLC.
| Registered Holder | Account Designation | Holding | |||||
| MAGIM HSBC GIS NOM(UK) | SALI | 95,887 | |||||
| PRUCLT HSBC GIS NOM(UK) | PAC AC | 25,075,000 | |||||
| PRUCLT HSBC GIS NOM(UK) | PPL AC | 1,129,918 | |||||
| Total | 26,300,805 |
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United Utilities’ ordinary shares trade on the London Stock Exchange and its ADRs, each equal to two ordinary shares, trade on the New York Stock Exchange under the Trading Symbol ‘UU’.
