Exhibit 99.1
SUMMARY
FORM6-K
SECURITIES AND EXCHANGE COMMISSION
Washington D.C. 20549
Report of Foreign Issuer
Pursuant to Rule 13a – 16 or 15d – 16 of
The Securities Exchange Act of 1934
Announcements sent to the London Stock Exchange
National Grid plc,1-3 Strand, London, WC2N 5EH, United Kingdom
Routine announcements in the period to 6 April 2018
| 05 April 2018 | Director/PDMR Shareholding | |
| 03 April 2018 | Total voting rights | |
| 26 March 2018 | Transaction in own shares | |
| 23 March 2018 | Transaction in own shares | |
| 22 March 2018 | Transaction in own shares | |
| 21 March 2018 | Transaction in own shares | |
| 20 March 2018 | Transaction in own shares | |
| 19 March 2018 | Transaction in own shares | |
| 19 March 2018 | Transaction in own shares | |
| 19 March 2018 | Director’s Other appointment | |
| 15 March 2018 | Transaction in own shares | |
| 14 March 2018 | Transaction in own shares | |
| 13 March 2018 | Transaction in own shares | |
| 12 March 2018 | Transaction in own shares | |
| 09 March 2018 | Transaction in own shares | |
| 08 March 2018 | Transaction in own shares | |
| 08 March 2018 | Director/PDMR Shareholding | |
| 07 March 2018 | Transaction in own shares |
Note: During the period a ‘same day’ Form6-K was issued in respect of the following National Grid plc announcements:
07 March 2018: Ofgem’sRIIO-2 Framework Consultation
16 March 2018: NIMO three-year rate plan approved
