NIM31019 - Special Cases: Widows: Widows who receive war widows pension
Regulation 127(8) of the Social Security (Contributions) Regulations 2001 (SI 2001 No. 1004)
The rules and procedures about reduced liability for ordinary widows also apply to war widows - whether or not the war widow is getting Bereavement Allowance (BA) - see NIM31018.