Director/PDMR Shareholding

1

Details of the person discharging managerial responsibilities / person closely associated

a)

Name

Mike Westcott

2

Reason for the notification

a)

Position/status

Group HR Director and Group Commercial Property Director

b)

Initial notification /Amendment

Initial notification

3

Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor

a)

Name

National Grid plc

b)

LEI

8R95QZMKZLJX5Q2XR704

4

Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted

a)

Description of the financial instrument, type of instrument

Identification code

Ordinary shares of 12 204/473p each

GB00BDR05C01

b)

Nature of the transaction

Monthly purchase of securities ("partnership

shares") under the HMRC Approved Share Incentive Plan

c)

Price(s) and volume(s)

d)

Aggregated information

- Aggregated volume

- Price

e)

Date of the transaction

2018.03.07

f)

Place of the transaction

London Stock Exchange (XLON)

Name of officer of issuer responsible for making notification: Robin Kerner.

Date of notification: 2018.03.08

1

Details of the person discharging managerial responsibilities / person closely associated

a)

Name

Alison Kay

2

Reason for the notification

a)

Position/status

Group General Counsel & Company Secretary

b)

Initial notification /Amendment

Initial notification

3

Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor

a)

Name

National Grid plc

b)

LEI

8R95QZMKZLJX5Q2XR704

4

Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted

a)

Description of the financial instrument, type of instrument

Identification code

Ordinary shares of 12 204/473p each

GB00BDR05C01

b)

Nature of the transaction

Monthly purchase of securities ("partnership

shares") under the HMRC Approved Share Incentive Plan

c)

Price(s) and volume(s)

d)

Aggregated information

- Aggregated volume

- Price

e)

Date of the transaction

2018.03.07

f)

Place of the transaction

London Stock Exchange (XLON)

Name of officer of issuer responsible for making notification: Robin Kerner.

Date of notification: 2018.03.08

1

Details of the person discharging managerial responsibilities / person closely associated

a)

Name

Andrew Bonfield

2

Reason for the notification

a)

Position/status

Finance Director

b)

Initial notification /Amendment

Initial notification

3

Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor

a)

Name

National Grid plc

b)

LEI

8R95QZMKZLJX5Q2XR704

4

Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted

a)

Description of the financial instrument, type of instrument

Identification code

Ordinary shares of 12 204/473p each

GB00BDR05C01

b)

Nature of the transaction

Monthly purchase of securities ("partnership

shares") under the HMRC Approved Share Incentive Plan

c)

Price(s) and volume(s)

d)

Aggregated information

- Aggregated volume

- Price

e)

Date of the transaction

2018.03.07

f)

Place of the transaction

London Stock Exchange (XLON)

Name of officer of issuer responsible for making notification: Robin Kerner.

Date of notification: 2018.03.08

1

Details of the person discharging managerial responsibilities / person closely associated

a)

Name

John Pettigrew

2

Reason for the notification

a)

Position/status

Chief Executive Officer

b)

Initial notification /Amendment

Initial notification

3

Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor

a)

Name

National Grid plc

b)

LEI

8R95QZMKZLJX5Q2XR704

4

Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted

a)

Description of the financial instrument, type of instrument

Identification code

Ordinary shares of 12 204/473p each

GB00BDR05C01

b)

Nature of the transaction

Monthly purchase of securities ("partnership

shares") under the HMRC Approved Share Incentive Plan

c)

Price(s) and volume(s)

d)

Aggregated information

- Aggregated volume

- Price

e)

Date of the transaction

2018.03.07

f)

Place of the transaction

London Stock Exchange (XLON)

Name of officer of issuer responsible for making notification: Robin Kerner.

Date of notification: 2018.03.08

1

Details of the person discharging managerial responsibilities / person closely associated

a)

Name

Lucy Nicola Shaw

2

Reason for the notification

a)

Position/status

Executive Director, UK

b)

Initial notification /Amendment

Initial notification

3

Details of the issuer, emission allowance market participant, auction platform, auctioneer or auction monitor

a)

Name

National Grid plc

b)

LEI

8R95QZMKZLJX5Q2XR704

4

Details of the transaction(s): section to be repeated for (i) each type of instrument; (ii) each type of transaction; (iii) each date; and (iv) each place where transactions have been conducted

a)

Description of the financial instrument, type of instrument

Identification code

Ordinary shares of 12 204/473p each

GB00BDR05C01

b)

Nature of the transaction

Monthly purchase of securities ("partnership

shares") under the HMRC Approved Share Incentive Plan

c)

Price(s) and volume(s)

d)

Aggregated information

- Aggregated volume

- Price

e)

Date of the transaction

2018.03.07

f)

Place of the transaction

London Stock Exchange (XLON)

Name of officer of issuer responsible for making notification: Robin Kerner.

Date of notification: 2018.03.08